Preparing for Phaser 2.2.1.
Fixed TweenManager.isTweening() and .removeFrom()
Updated invalid reference Tween._object to .target
Merge pull request #1408 from jotson/dev

Fixed TweenManager.isTweening() and .removeFrom()
Reverted changes as they broke all alpha support. Will put back once fixed in Pixi.
Updated readme.
Added Game.debug reset method for when the debug manager is disabled (thanks @DanielSitarz #1407)
Custom Particle classes that used a BitmapData wouldn't work (thanks @hardalias #1402)
And Pixi fixed the premult alpha issue properly. Back in again!
Docs update.
Phaser 2.2.1.
API Docs update.
Merge remote-tracking branch 'origin/dev'