REVERT: "overcrowded message no longer for factories supplied by producer but only interchanges": overcrowding should have economic consequences (slower transfer times), to be implemented.
Merge branch '112.5-merge' of git://github.com/BerndGabriel/simutrans-experimental.git into 112.5-merge
Merge branch '112.5-merge' of git://github.com/BerndGabriel/simutrans-experimental.git into 112.5-merge
Merge branch '112.5-merge' of git://github.com/BerndGabriel/simutrans-experimental.git into 112.5-merge
Fixed preliminarily: exception while deleting world.
Changed: some tiny performance optimizations.