Support for cocos2d-x

Because DragonBones change the output data, we cannot analysis directly, so we did some change.

1.We find the FrameData's x change to TransformX, but we need to use x, so we add an attribute - "cocos2d-x" "cocos2d-y"
2.Outputing 2 .xml is too much, so i combine skeleton.xml and texture.xml when choosing "zip(xml and PNGs)".  And i also add an attribute ""cocos2d-px" "cocos2d-py"" for the "SubTexture", 

Thanks for DragonBones!