Added functions to get the version of Lua being used.
Added implementation for Lua 5.1 layer.
Removed Lua 5.2 header since it is no longer necessary. Each Lua implementation will be conditionally compiled against luaapi.h.
Print the version of Lua that was built into the executable.
Added basic Makefile to build against the specified version of Lua.
Added Emacs temporary files to gitignore.