Lua Leveldb Versions Save

• The Cpp serializer has been removed in favor of a simpler storage.
• The sources now are divided into multiple source files.
• Support for Lua 5.1/5.2/5.3
• More testing needed for LuaJIT.

The storing procedures were completely rewritten, now lua values are directly translated into byte arrays and stored into a leveldb's Slice, a new simple layer of serialization does the job o serializing lua values and translate them back from leveldb. So now the types are completely transparent to the developer.

For now the storable types are: strings, numbers and booleans.

Now the making procedure is completely make/luarock based and so I removed the old scripts.

Thanks to daurnimator now lua-leveldb is 5.2 compatible, unfortunately we lost compatibility with Lua 5.1.