Nested Assets

This update addresses nesting of Assets, specifically the new AssetViews. This required a wholesale refactoring of FlexItems, because nested views were getting created (instantiated) well in advance of actually being associated with a MovieClip, and FlexItems need to know the clip before they can do their magic.

FlexItems can now defer their update cycle until the AssetView gets its clip.

Adding a nested AssetView to a "parent" AssetView is the same as adding a ScreenAssetView to a ScreenView: addAsset(). This ensures that the child asset is registered with the parent, and allows the parent to bubble up activate(), deactivate(), localize(), setupBeforeLocalize() and setupAfterLocalize(), among others.

TransitionManager hotfix

Discovered a breaking error in the way transitionOut and transitionIn were sequenced. This needed to be fixed at once, because TransitionBase, which is the default Transition, was broken as a result.

I should test more before tagging something as a release.

TransitionManager Overhaul

This release overhauls TransitionManager and moves responsibility for managing a screen's "Out" transition (the transition that gets used when leaving a screen) from the App (which was silly) to the ScreenView itself.

This creates a much more intuitive workflow, and makes it a lot easier for a Screen to set its own transition, even set a different transition depending on what user interactions caused the Screen to exit.

Now, use ScreenView.TransitionOut setter to set any subclass of TransitionBase (including TransitionBase, if you want a straight cut) prior to calling ScreenRouter.setScreen() and you'll get the expected transition.