Expose the current mode stack length.
(cherry picked from commit 5dc345261d985ce8373b22833f3f29a6c81fb698)
Compatibility with Starling master branch

Flashbang no longer relies on a fork of Starling; a recent Starling
exposed TouchProcessor for subclassing, which allows us to ditch our one
outstanding Starling patch.
Merge pull request #5 from roguenet/expose-mode-stack-length

Expose the current mode stack length.
SimpleTextButton: fontName parameter
Compatibility with starling input changes, take 2

Starling's TouchProcessor now supports dispatch on non-stage
DisplayObjectContainers, so we don't have to implement that
functionality
MovieButton: don't error if we don't have all the button states
Mouse wheel event support
TouchListeners no longer consume individual touches

You either consume everything or nothing; touches are rarely discrete