fix duplicate entry in ruleset
fix visibility in smoke
double check that math.

again, thanks to bresenham doubling, this is some confusing stuff, but this
multiplication throws the formula off in our case.
zombify units BEFORE endturn
fix some offscreen behaviour.
Merge branch 'master' of https://github.com/SupSuper/OpenXcom into Kmod

Conflicts:
	src/Battlescape/TileEngine.cpp

Conflict wasn't important - simply accepted SupSuper's code.