yui event

http://chunghe.googlecode.com/svn/trunk/experiment/yui.event/yui.event.htm

addListener/remoevListener/getListeners
1. removeListener must specify the event type, ex: Event.removeListener('foo', 'dblclick', hello)
2. getListeners doesn't have to specify the event type, ex: Event.getListeners('foo')

focusin / focusout
1. DOM focus and blur events don't bubble, use YUI focusin & focusout event to solve.
2. By giving it a tabindex you can make any element you like focusable. The focus and blur events should work on such elements.

event delegate (with mouseenter/mouseout)
1. event delegate needs selector.js for the fourth argument