YUI Custom Events

    Custom event system

3.0.0

    - Broken into core base and complex modules.

    - broadcast works for simple events.

    - If configured to return an event handle, the return value

      will always be a single object, regardless of how many listeners

      were attached.  Previously, multiple listeners provided an array

      of detach handles.

3.0.0beta1

    - Implemented the broadcast flag.  broadcast = 1: local, accessible

      via Y.on('prefix:event'). broadcast = 2: global, accessible

      via Y.on or globally via Y.Global.on('prefix:event).  Broadcast 

      listeners cannot effect the defaultFn or host subscribers (so

      are in effect, after listeners), although this is still possible

      by added either Y or Y.Global as event targets.

    - Moved custom event out of event package

    - EventTarget 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.

    - Event type accepts a event category which can be used to

      detach events.  

      Y.on('category|prefix:event', fn);

      Y.detach('category|prefix:event');

      Y.detach('category|*');

    - Added 'chain' config to events that makes the return value the 

      event target rather than a detach handle.  Use with the detach

      category prefix.

    - The type parameter can be an object containing multiple events to attach

      Y.on( { 'event1': fn1, 'event2': fn2 }

    - Y.fire payload for event facades can be another facade or a custom event.