Readme update.

Author: photonstorm

README.md

@@ -363,6 +363,7 @@ Version 2.4 - "Katar" - in dev
 * Rope constructor was fixed enabling it again (thanks @gionatan7 #1799)
 * FrameData.getFrameIndexes when called with a partial array (such as creating an animation out of a set of frames) would return the indexes array padded out with 'undefined' entries, causing short animations to never fully play through.
 * AnimationManager.add no longer sets the `currentFrame` property when just adding an Animation to a Sprite. The `currentFrame` property is now only set when the animation begins playing. This avoids the Sprite.frame and Sprite.frameName properties from returning incorrect results after adding (but not playing) an Animation. It also allows very short animations (2 frames) to play correctly without needing to loop.
+* PIXI.Graphics was calling Polygon.flatten in its drawShape call, causing the original Polygon object to internally change. It now takes a clone of the polygon and only flattens that (#1779)
 
 For changes in previous releases please see the extensive [Version History](https://github.com/photonstorm/phaser/blob/master/CHANGELOG.md).