Merge pull request #7 from megax/master

Makefile update
Removing GLOBALINDEX from NLuaRemoving GLOBALINDEX from NLua
Bumped Lua
Added registry index API.
Fixed lua_registryindex
Added functions to compatibility between Lua 5.1/ 5.2
Added luanet_pushlstring. (lua_pushlstring have different signature in 5.1/5.2)
Update KeraLua to Lua 5.2.2
Fixed gendarme warnings (hight+)
Added EntryPoint to NativeMethods.
Renamed Methods from snake_case to CamelCase.
Removed warning from gendarme
Un-nest public classes.
Fixed iOS build.
Added Win64 bat
Bumped Lua
Fixed 64bit build