Added information about skill used to gun mods and fixed segfault when firing a mod
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
Merge pull request #5296 from CIB/master

Added bindings for revive and mon_at to lua.
Merge pull request #5294 from Voker57/gunmodfix

Added information about skill used to gun mods and fixed segfault when firing a mod