Update lua dependency to 5.2.3
Add lua_cjson module

Downloaded from https://github.com/mpx/lua-cjson/tree/d59326b2d718e1a140b9b396ffe0a557b2d93fe0
Add lua_cmsgpack

Downloaded from https://github.com/antirez/lua-cmsgpack/tree/c600e0a13866cf3d07774870dcea904e7b442d81
Add lua_struct

Downloaded from https://raw.githubusercontent.com/LuaDist/struct/7a950abb3e7b1884462a920e4853bab63edf2cd3/struct.c
Compile with Lua 5.2