[Core] Added UIMenuBar's bindings to FrameworkLuaLib;
[Core] Added LuaEventGroup;
[Core] Added UIPanel Properties Lua Table;
[Core] Added UIPanel Event Bindings to FrameworkLuaLib;
[Core] Made SoundManager reuse Sounds and Musics;
[Core] Added Cleanup to SoundManager;
[Core] Added Lua On Item Selected Callback for UIMenuBar;