if ( !window.requestAnimationFrame ) {

	window.requestAnimationFrame = ( function() {

		return window.webkitRequestAnimationFrame ||
		window.mozRequestAnimationFrame ||
		window.oRequestAnimationFrame ||
		window.msRequestAnimationFrame ||
		function( /* function FrameRequestCallback */ callback, /* DOMElement Element */ element ) {

			window.setTimeout( callback, 1000 / 60 );

		};

	} )();

}

function __extend__(subClass, superClass) {
	
	var F = function(){};
	F.prototype = superClass.prototype;
	subClass.prototype = new F();
	subClass.prototype.constructor = subClass;
	
	subClass.superClass = superClass.prototype;
	if(superClass.prototype.constructor == Object.prototype.constructor) {
		superClass.prototype.constructor = superClass;	
	}
	
}