Fixes some ZAS issues and improves air alarms some.

Reverts my firechanges, since they were awful.  Made space have a heat capacity of 1 instead of 700000, but due to how mobs work (which makes me want to murder someone) this has no effect on how rapidly you freeze in space.  Also fixes excessively slow decompression.

Fixes #3076
Fixes #3197 (Sorta)