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General
* Added support for overriding target backends
Native
* Added Point.setTo
* Added Rectangle copyFrom, toString
* Added Matrix copyFrom, copyRowTo, copyRowFrom
* Added Matrix copyColumnTo, copyColumnFrom, setTo, toString
* Fixed a rare issue in the static initialization order
* Fixed displayObjectContainer.contains
* Improved bitmapData.dispose
HTML5
* Improved Lib.getURL
* Fixed loaderInfo.parameters
* Added flash.external.ExternalInterface
* Improved handling of touch and mouse events