Added bindings for revive and mon_at to lua.

Also fixes a few bugs, including:
- lua script was called after loading JSON files, which led to lua iuse's not being available
- the pcall for iuse's had the wrong parameters, leading to constant errors on lua iuse's

See https://github.com/CIB/Cataclysm-DDA/commit/a3256fa02bc1c4267ed7137fe13cbd300d684548 for a test case to prove that the changes in this commit actually work. =)