issue #5121, fix LoadingBar percentage when initialize
closed #5121, change percentage from int to float
closed #5121, add const to getPercent method
Merge pull request #6697 from CocosRobot/update_lua_bindings_1399952323

[AUTO]: updating luabinding automatically
Merge pull request #6696 from andyque/issue5121

issue 5121, fix loading bar init flicker and refator percentage