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.
Replace open-coded is_outside() with simple loop.
descending stairs, using an elevator, and

debug-teleporting no longer crash when
right next to overmap borders. stuff was only
being dynamically generated for one of the overmaps.
Changed material type to POWDER for granular and splattery foods.
Added plastic jars to store food.
Bugfix in reloading jars and water containers.