Update ZipToGAFAssetConverter.as

Added an id property to the zipConverter to know which one is it on event callback when I'm using severals converters dynamically and I need to use an arbitrary id unrelated to the GAFAsset's id.
Merge pull request #3 from Fraggle/patch-1

Update ZipToGAFAssetConverter.as
Various changes and optimisations.

• GAFMovieClip are no longer frame based but time based, by default they respect the fps from gaf converter but you can change override it
• GAFMovieClip now use starling's main juggler instead of ENTER_FRAME event
• [Breaking Change] SequenceEvent are removed and Starling's Event with custom type are used instead, with pooling.
• Added 2 new events types: GAFMovieClip.EVENT_TYPE_SEQUENCE_SKIP_START, GAFMovieClip.EVENT_TYPE_SEQUENCE_SKIP_END dispatched if the movieclip had to skip thoses sequences events.
• GAFMovieClip do not clear the full display list on each frame, it set all children's visibilty to false (avoid dispatching lots of events and creating temporary arrays)
• GAFMovieClip.setSequence() now has a third optional parameter "loop" (false by default)
• Added CAnimationFrameIntance.applyTransformMatrix() and call it instead of getTransformationMatrix() when possible to avoid creating many temporary matrix in each draw()