Scroller: added horizontalPageCount and verticalPageCount (closes #420)
TileList: uses new horizontalPageCount property.
Scroller: hides scroll bars when stopScrolling() is called (closes #426)
DisplayListWatcher: added exclude() and isExcluded() (closes #334)
Button: added some inline example code.
Scroller: event listener name includes scroller_ to avoid confusing conflicts in subclasses
YouTubeFeeds: updated to use PanelScreen
BitmapFontTextRenderer: skipped characterBatch positioning in render() if null (closes #443)