/**

* @license
* ==========================================================================
* SproutCore Costello -- Property Observing Library
* Copyright ©2006-2011, Strobe Inc. and contributors.
* Portions copyright ©2008-2011 Apple Inc. All rights reserved.
* 
* Permission is hereby granted, free of charge, to any person obtaining a 
* copy of this software and associated documentation files (the "Software"), 
* to deal in the Software without restriction, including without limitation 
* the rights to use, copy, modify, merge, publish, distribute, sublicense, 
* and/or sell copies of the Software, and to permit persons to whom the 
* Software is furnished to do so, subject to the following conditions:
* 
* The above copyright notice and this permission notice shall be included in 
* all copies or substantial portions of the Software.
* 
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR 
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, 
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE 
* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER 
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING 
* FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER 
* DEALINGS IN THE SOFTWARE.
* 
* For more information about SproutCore, visit http://www.sproutcore.com
* 
* ==========================================================================
*/