Add zoom function to FP.screen

[mbroersen]

I'd like to add this to the screen class:

    /**
     * Zoom full screen.
     */
    public function zoom(scale:Number):void 
    {
        this.scale = scale;

        var width:int = FP.width / this.scale;
        var height:int = FP.height / this.scale; 

        FP.bounds.width = width;
        FP.bounds.height = height;

        this.resize(width, height);
    }


    /**
     * Initialise buffers to current screen size.
     */
    public function resize(width:int = 0, height:int = 0):void
    {
        if (width <= 0) {
            width = FP.width
        }

        if (height <= 0) {
            height = FP.width
        }

I tested the code a little bit, don't know if it causes any trouble in other bits of the code. but my test ran fine.