FIX: Crash on loading in some cases (ultimate cause unknown).
CHANGE: Reduce the maximum number of ships on a tile to prevent ship overflows (as recommended by TurfIt)
CHANGE: Optimise fix for loading errors.
Merge branch '11.x' into 12.x
Merge branch '12.x' into devel-new
Merge branch 'devel-new' into 112.5-merge