check whether the map's submap grid

is somehow corrupted,
before adding a spawn point to it.
fixed segfault on flooding strange temple room
Let webs be woven over slime.

Both web weaver and slimy are mutations that can coexist.
Vehicle part cache optimization.

Hopefully fixing the situation where the game is bogged down
with vehicle cache map traversals when there are a
bunch of mobs & vehicles around.
 #include stdint.h in skill.h so that it compiles