WIP commit: Adding lua scripting capabilities.

- Initialized lua 5.1
- Wrapped game->add_msg for lua use
- Made Use_function's into a class that can use either lua or C++ functions
- Added a function for lua to register lua functions as iuse's
- Relies on a lua5.1/ include directory and a -llua5.1 link library being present
A wrapped item userdata is now passed on to lua iuse functions.

Only the id item member is wrapped so far.
Worked on a new lua binding generator, customized for cataclysm.
Updates and fixes.