Version：4.2.1 Date：2015-10-9
Update the content：
【Add】 added the type of "basic animation project", which is suitable for making tween animation without skeleton relationship.
【Add】support exportation of Egret MovieClip data format.
【Add】 open import plug-in standard, allowing users to write and install the import plug-in.
【Add】added Cocos import plug-in, which supports importing Cocos 1.x skeleton animation.
【Enhancement】Strengthen the Spine import function to support the import of texture sets in the Spine format.
【Enhancement】 enhance timeline operation, support drag and drop, box selection, pan and scale after box selection, and paste key frames across animations.
【Fix】Fixed several AS and TS library bugs.