function SpriteSheetBuilder(framerate) {
		this.EventDispatcher_constructor();
		
	// public properties:
		/**
		 * The maximum width for the images (not individual frames) in the generated SpriteSheet. It is recommended to
		 * use a power of 2 for this value (ex. 1024, 2048, 4096). If the frames cannot all fit within the max
		 * dimensions, then additional images will be created as needed.
		 * @property maxWidth
		 * @type Number
		 * @default 2048
		*/
		this.maxWidth = 2048;
	
		/**
		 * The maximum height for the images (not individual frames) in the generated SpriteSheet. It is recommended to
		 * use a power of 2 for this value (ex. 1024, 2048, 4096). If the frames cannot all fit within the max
		 * dimensions, then additional images will be created as needed.
		 * @property maxHeight
		 * @type Number
		 * @default 2048
		 **/
		this.maxHeight = 2048;
	
		/**
		 * The SpriteSheet that was generated. This will be null before a build is completed successfully.
		 * @property spriteSheet
		 * @type SpriteSheet
		 **/
		this.spriteSheet = null;
	
		/**
		 * The scale to apply when drawing all frames to the SpriteSheet. This is multiplied against any scale specified
		 * in the addFrame call. This can be used, for example, to generate a SpriteSheet at run time that is tailored
		 * to the a specific device resolution (ex. tablet vs mobile).
		 * @property scale
		 * @type Number
		 * @default 1
		 **/
		this.scale = 1;
	
		/**
		* The padding to use between frames. This is helpful to preserve antialiasing on drawn vector content.
		* @property padding
		* @type Number
		* @default 1
		**/
		this.padding = 1;
	
		/**
		 * A number from 0.01 to 0.99 that indicates what percentage of time the builder can use. This can be
		 * thought of as the number of seconds per second the builder will use. For example, with a timeSlice value of 0.3,
		 * the builder will run 20 times per second, using approximately 15ms per build (30% of available time, or 0.3s per second).
		 * Defaults to 0.3.
		 * @property timeSlice
		 * @type Number
		 * @default 0.3
		 **/
		this.timeSlice = 0.3;
	
		/**
		 * A value between 0 and 1 that indicates the progress of a build, or -1 if a build has not
		 * been initiated.
		 * @property progress
		 * @type Number
		 * @default -1
		 * @readonly
		 */
		this.progress = -1;

		/**
		 * A {{#crossLink "SpriteSheet/framerate:property"}}{{/crossLink}} value that will be passed to new {{#crossLink "SpriteSheet"}}{{/crossLink}} instances that are
		 * created. If no framerate is specified (or it is 0), then SpriteSheets will use the {{#crossLink "Ticker"}}{{/crossLink}}
		 * framerate.
		 * @property framerate
		 * @type Number
		 * @default 0
		 */
		this.framerate = framerate || 0;
	
	
	// private properties:
		/**
		 * @property _frames
		 * @protected
		 * @type Array
		 **/
		this._frames = [];
	
		/**
		 * @property _animations
		 * @protected
		 * @type Array
		 **/
		this._animations = {};
	
		/**
		 * @property _data
		 * @protected
		 * @type Array
		 **/
		this._data = null;
	
		/**
		 * @property _nextFrameIndex
		 * @protected
		 * @type Number
		 **/
		this._nextFrameIndex = 0;
	
		/**
		 * @property _index
		 * @protected
		 * @type Number
		 **/
		this._index = 0;
	
		/**
		 * @property _timerID
		 * @protected
		 * @type Number
		 **/
		this._timerID = null;
	
		/**
		 * @property _scale
		 * @protected
		 * @type Number
		 **/
		this._scale = 1;
	}
The SpriteSheetBuilder allows you to generate {{#crossLink "SpriteSheet"}}{{/crossLink}} instances at run time
from any display object. This can allow you to maintain your assets as vector graphics (for low file size), and
render them at run time as SpriteSheets for better performance.

SpriteSheets can be built either synchronously, or asynchronously, so that large SpriteSheets can be generated
without locking the UI.

Note that the "images" used in the generated SpriteSheet are actually canvas elements, and that they will be
sized to the nearest power of 2 up to the value of {{#crossLink "SpriteSheetBuilder/maxWidth:property"}}{{/crossLink}}
or {{#crossLink "SpriteSheetBuilder/maxHeight:property"}}{{/crossLink}}.
@class SpriteSheetBuilder
@param {Number} [framerate=0] The {{#crossLink "SpriteSheet/framerate:property"}}{{/crossLink}} of
{{#crossLink "SpriteSheet"}}{{/crossLink}} instances that are created.
@extends EventDispatcher
@constructor