Merge pull request cocos2d#2929 from pandamicro/develop

Fixed cocos2d#2926: Activate premultiplied alpha

Author: pandamicro

cocos2d/core/platform/CCConfig.js

@@ -117,7 +117,7 @@ cc.SPRITEBATCHNODE_RENDER_SUBPIXEL = 1;
  * @constant
  * @type {Number}
  */
-cc.OPTIMIZE_BLEND_FUNC_FOR_PREMULTIPLIED_ALPHA = 0;
+cc.OPTIMIZE_BLEND_FUNC_FOR_PREMULTIPLIED_ALPHA = 1;
 
 /**
  * <p>