Global mountains changes : mountains around lakes are removed + terraforming of mountains clusters depending of their size
While not entirely perfect, these changes should greatly reduce the chances to get blocked by mountains.
Each mountain have a chance to be terraformed, increasing linearly with cluster size. So tiny clusters remain unchanged and bigger are reduced in size. This do not guarantee you will get a way through every time, but definitely should help to get more space for cities. Volcanoes are not terraformed.

Other quick fixes
Fix from previous coastal change in 1.10 : now is a score malus instead of restriction that could lead to firaxis when coastal spawns are limited (like in EvW)
References this note in 1.10 :
Fix some cases where there is not enough space to add resources on water ring 2. So naval civ should now avoid "corridors" of water like 1 tiles ring 1 + 1 tile ring 2.

Removed ice on coast 4 tiles around spawn
Ice algo is the same for all maps and didn't want to make big changes for rare cases in highlands where ice go beyond tundra, will work later on a better fix if needed.

I still do not have enough data for the lux issue when there is none on the spawn as it seems very rare. Please send me the save when this happens.

Minimum yields in ring 1-2

The ring 1 now has a minimum of 2x 4yields tiles, including one guaranteed 2/2. The algo will not add a 4/0 by itself but these tiles can already exist before the algo.
Like before, 3x 2/2 are guaranteed on ring 1+2 and there is the 3+ food tiles guaranteed.

Spawn one tile off coast will grant a fish on ring 3 if there is less than 3 sea resources (crabs excluded)

For helping spawns needing to settle coast while not spawning directly on it, a fish is added to help if there is not enough sea resources or no fish at all. (Crabs not included in the analysis).

Sea resources fix

There is a limited amount of luxuries and strategics sea resources possible to place on the map, but the chance to add them is quite high while scanning the map and goes from west to east. As a result, most of these resources end up missing in the east side of the map quite often.
Now, luxuries and strategics resources on water will be randomly distributed on the map.
NOTE : Bonus resources such as fishes and crabs are NOT changed !

Fix desert teraforming that was 100% into plains into a mix of grassland and plains

In 0.95 the desert terraforming around the spawn was only into plains, now it can also terraform into grassland to avoid huge patches of only plains. Plains will still be a bit more frequent.

Maya hydrophobic bias fix

In some cases, Maya would find itself with not enough valid tiles for its bias and get into the "generic" valid tiles list to be placed on, ending up on the coast. A malus in the score has been added to discourage getting close to the coast if we get into this situation.

Moutains and Inca bias update

The goal is to reduce occurrences of these civ spawning in huge patches of mountains.
To help this, BBM now favors spawns with more walkable tiles (technically "peninsula score") and the bias score has been recalculated to reduce the maximum amount of mountains to reach the max score.

East Vs West changes :
Bugfix : The placement order was not taking the East Vs West feature into account, as a result, not placing the most restrictive civ first. This is now fixed and you should expect less firaxis placements, but beware it can still happens for a few reasons ! (mostly map generation, restrictive civs, etc.)

East Vs West now works with any team size.
For odd team number, the additional player should be placed on sim to work properly. (In 5v5, the first 6 players on sim, the last 4 on front).
You can duel with it and the center of the map will not be used for placement.

Other changes :
The restriction of 2 impassable tiles in a row ring 1 for non coastal civ (introduced in v0.93) is now a malus in spawn score instead of a forbidden spawn. This allow this spawn to still happen if it is the last resort instead of getting firaxis placement.

Huts bugfix for 0.93

Features changes :
East vs West setting available on Pangaea and Continents for 4v4 and 2v2
Placement rules an settings should be the same as BBS option (first half in lobby 4v4 = sim, bottom half = front) but take note that BBM has stricter placement conditions that may lead more often to firaxis placement (seen by a barbarian icon on turn 1). Avoid coastal and tundra on war position. As I almost never played this on BBS myself I am counting on your feedback to improve this feature !

Hills percentage in ring 6 have now a minimum based on the global hill percentage, additional hills can be added randomly ring 6 to reach that minimum on existing resourceless flat tiles, possibly on forest or jungle.
On most maps with old age setting, global hill percentage is around 35%, that percentage was not always reflected around some spawns (especially on highlands where percentage is closer to 55%).

Non coastal spawn with 2 impassable tiles in a row ring 1 are now forbidden. This allow placement to be slightly adjusted to be at the edge of big lakes or mountains chains and reduce the risk of having a spawn where these impassable tiles are increasing settling time of the few first cities.
It has been reported a few times that in some mountains or lakes setup, b2 or b3 were too long to settle or forced in a direction. In most cases, spawn could have been improved just by spawning one tile next to the spawn at the edge of the obstacles or another close tile. This is what this change aims to do without affecting other placement.

Ice tiles number on maps is now scaling on water tile percent on map.
Up to now, algo had a fixed number of desired ice tiles on any map, regardless of the number of available water tiles. Which made leaded to weird behavior on highlands and lakes especially. Unchanged for other maps.
Hut density should be more homogeneous globally in some cases.
Hut density could be exceptionally high on west coast on Pangaea due to bad default algo. In short, when scanning the ocean, the "score" overflows for being unable to add huts and compensate when he could add them. As the scanning went from west to east, west coast of pangaea was overflowed. This has now been prevented. Others placements rules have not been changed and is still compatible with Configurable Goody Huts mod.

City states will not spawn on tiles completely surrounded by impassable tiles (water or mountains)

Hut density should be more homogeneous globally in some cases.
Hut density could be exceptionally high on west coast on Pangaea due to bad default algo. In short, when scanning the ocean, the "score" overflows for being unable to add huts and compensate when he could add them. As the scanning went from west to east, west coast of pangaea was overflowed. This has now been prevented. Others placements rules have not been changed and is still compatible with Configurable Goody Huts mod.

City states will not spawn on tiles completely surrounded by impassable tiles (water or mountains)

As requested for future competitions, here is the official list of compatible maps with BBM for now :
Pangaea / Highlands (+Rich) / Lakes / Inland seas / 7 seas / Primordial / Tilted axis / Continents / Continents & islands / Small continents / Wetlands / Fractal / Splintered fractal / Island plates / Terra
Among defaults generated firaxis maps, Archipelago and Shuffle are not compatible with BBM and it is now mentioned in a tooltip on game start. True starts, Mirror and fixed maps like snowflake are also excluded.

Added Portuguese translation by @Rafael Pinheiro

Bugfixes :
Fixed an issue where guaranteed luxuries could be deleted because they were high yields tiles. Hills are removed instead on these luxs.
Fixed an issue where high yields tiles in ring 1 or 2 would not be nerfed properly
Fixed an issue where Vesuvius was disguised as a normal volcano
Fixed volcanoes spawning on lake in rare cases
Fixed a bug where a strategic resource could terraform a floodplains to hills.
Fixed ring 3 fish in ocean
Fixed compatibility with BBG,

* Minimum distance setting is back and working.
> Take note that if BBM has a hard time finding bias or if minimum conditions can not be satisfied for everyone, it will lead to firaxis placement.

**Bugfixes :**
* Classic ridges Primordial have volcanoes again

* Fixed an issue where tiles with 1 food 3 prod and extra yields (culture/science/faith/3 golds) were not correctly labeled as "high yield"
> It could lead to spawn with 3/2 + 1/3/1 ring 1 or 2 that should have been prevented

* For civs spawning coastal, turtles will no longer be added if the maximum lux threshold is reached.
> 3 is the maximum number of luxuries up to ring 3 and turtles could be added ignoring this limit.

* Fixed an issue where the 3+ food tile ring 2 could be moved to ring 3 if it was an existing high yield tile (3/2 or 5/0)

* Fixed geothermal fissure that could be flattened by the yield balancing algo and therefore could be settled turn 1

* If played without BBG, BBM should now read correctly the default biases and use them.

Feature changes :
Prevent settling on geothermal fissure on turn 1
You should no longer spawn on geothermal fissure and existing fissures ring 1 and 2 are changed to hills to prevent turn 1 settle.

Bugfixes :
High yields balancing for tundras civ is now working properly
Only "high yields" tiles for in tundra tiles are 1/3 deers, they can now correctly be added (if absent) on teamer during high yields balancing algo introduced in v0.90.

Fix infinite loading in some situations
Two infinite loops cases were identified and corrected that mostly happened in duels and sometimes with tundras civ.

Fix a crash that happen when you launch BBM without BBG with custom bias civ (still would not recommend to do so but for now game starts correctly)

Updated french description for natural wonders