YUI Custom Events

Custom event system

3.0.0b1

- Moved custom event out of event package

- Event.Target accepts a prefix configuration. This is used

in all exposed methods to handle shortcuts to event names,

e.g., 'click' and 'menu:click' are the same if the prefix

is 'menu'

- Exposed methods are 'on' for the before moment, 'after' for

the after moment, and 'detach' for unsubscribe. subscribe,

before, unsubscribe, and corresponding methods are deprecated.