yui- to yui3- in classnamemanager and css files

Split 'widget' module into sub-modules. Made kweight optimization pass. Removed moveStyles support (beta feature, which is not currently used/required). Made render event fireOnce. Renamed DOM_EVENTS to UI_EVENTS and changed supporting method names accordingly (DOM_EVENTS added recently, post 3.0 - will require WidgetParent/WidgetChild sync up). 'widget' rollup module funcitonality should remain unchanged apart from moveStyles removal, and DOM_EVENTS related name changes. Ran through test cases and examples on FF/Safari/IE. README has details