Further reduce number of calls to map::ter() by caching the value and referencing it multiple times in build_outside_cache().
Recuce calls to map::ter() a little more by stashing the value locally.
Merge git://github.com/kevingranade/Cataclysm
Merge branch 'master' of https://github.com/TheDarklingWolf/Cataclysm-DDA