Fixes the chicken problem
There are no more unreachable trees around the map (hopefully)
Fixed the bug that caused edges of the map ruin the layout of painters
(One of the best examples to look is archipelago, before and after this
revision).
Fixed those out of memory errors caused by pathplacer (Mostly noticeable
in alpine valley and corinthian isthmus)
And some other minor tweaks.
Fixes#1577
This was SVN commit r13004.
