spawner fix, when anything fails during the spawner "spawn" phase, it gets removed from the list, thus not blocking other spawners, the error gets reported in keen log

/npc economy sellprefabs command fixed to properly handle free ports

MinimalPricePerUnit 0 is not being used for price calculation of prefabs

commenting out some unfinished code

automatic data cleanup on init fixed, missing null check when no ownership and no siege defs existed

added missing EnablePlanetaryEncounters override to the NPC Provider world config setter

added toggle to force certain world config variables to ensure compatibility with the NPC Provider (enabled by default, can be disabled in PersistentData.xml

minor code cleanup

redundancies

planets have additional information in /npc info and in mission description (distance to world center 0;0;0). This allows to differentiate planets with the same generator id.