Changed mean time of planet growth back to original 1 tile per year.

Slightly lowered the chance the donor planet gains an extra +1 to mineral deposit each time it shrinks. Now the total bonus should be +2 in total for overmined donors.

Now ensuring there is at least one minable donor planet happens dynamically: if it is found that there are no such planet left inside the empire borders, one of donor-type planet with no deposits get +1 mineral so the mining station can be built upon that. In result the +1 mineral rocks do not appear everywhere at once, but show up gradually.
My apologies to those who get their savegames cluttered with 1-mineral rocks everywhere. :)

-Now growing planets drain any celestial object mined by a Mining Station of the Empire (no restriction to be in the same system anymore). The following planet types are used as donors (assuming they have mining station built over them):
pc_barren
pc_barren_cold
pc_frozen
pc_asteroid

-To ensure those types of planets can all be mined by a mining stations, each one got +1 mineral deposit in case it had nothing at all.

-Each time a donor get drained there is a chance it will be enriched by +1 mineral deposit.

-Donors are not drained to extermination any more - the minimum size the celestial object is allowed to get shrunk to is 3.

-Planets with anomalies and planets that are terraforming candidates are not accepted as donors.

-Removed the popup informing that there are no more mass left for planet to grow since this situation will hardly ever happen now.

-Removed the restriction preventing planets with colonizable satellites to not be accepted as donors.

-Growth event happens approximately twice a year now (instead of once a year).

-Changed the description of the Terraforming Station.

The contents of this mod are shown here for those of u who r interested.

Added message notifying the player if there are no more celestial bodies left in the system that can be scraped for matter.
Added message notifying the player when planet is fully grown.
Planets that can be colonized are not accepted as donors any more.
Planets that have colonizable satellites are not accepted as donors any more.
Donor planets have chance to be destroyed completely unless they have strategic resource on them.
For donor planets with ring the ring disappears first instead of size shrink.
For donor planets with satellites it is ensured that the main planet will stay larger than it's satellites.

Oh yes! Now it works correct - the main planet grows ONLY if there is a donor planet/asteroid that shrinks. If there is no suitable astronomical object left in the solar system, the main planet will not grow any more.

An improvement to consistency: now along with the growth of a planet another uninhabitable planet in the same system shrinks in size. However, the mechanic is not perfect yet - even if there is no suitable "donor" planet found in system, the main planet will still grow. Trying to find a workaround to make things perfect, but a first step in the right direction is made.

Small optimizations made as well - now event is automatic, not triggered by on_action. Users don't care, but I just saying. :)

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