Merge pull request #9 from megax/master

The missing 5.1.5 updates were built-in in the code.
Added functions to compatibility between Lua 5.1/ 5.2
Added luanet_pushlstring. (lua_pushlstring have different signature in 5.1/5.2)
Update LuaTests
Renamed methods from snake_case to CamelCase
Renamed lua_State -> LuaState
Un-nest public classes.
Fixed Build
Fixed WP7 build.
Fixed Loadlib for WP/Silverlight