function Shadow(color, offsetX, offsetY, blur) {
		
		
	// public properties:
		/** 
		 * The color of the shadow. This can be any valid CSS color value.
		 * @property color
		 * @type String
		 * @default null
		 */
		this.color = color||"black";
	
		/** The x offset of the shadow.
		 * @property offsetX
		 * @type Number
		 * @default 0
		 */
		this.offsetX = offsetX||0;
	
		/** The y offset of the shadow.
		 * @property offsetY
		 * @type Number
		 * @default 0
		 */
		this.offsetY = offsetY||0;
	
		/** The blur of the shadow.
		 * @property blur
		 * @type Number
		 * @default 0
		 */
		this.blur = blur||0;
	}
This class encapsulates the properties required to define a shadow to apply to a {{#crossLink "DisplayObject"}}{{/crossLink}}
via its <code>shadow</code> property.

<h4>Example</h4>

     myImage.shadow = new createjs.Shadow("#000000", 5, 5, 10);

@class Shadow
@constructor
@param {String} color The color of the shadow. This can be any valid CSS color value.
@param {Number} offsetX The x offset of the shadow in pixels.
@param {Number} offsetY The y offset of the shadow in pixels.
@param {Number} blur The size of the blurring effect.