function rotate(degrees, immediately) {
        _setTransformRotate(_this.displayRegionContainer, degrees);
        _setTransformRotate(_this.displayRegion, -degrees);
        _this.viewport.setRotation(degrees, immediately);
    }
@class Navigator
@classdesc The Navigator provides a small view of the current image as fixed
while representing the viewport as a moving box serving as a frame
of reference in the larger viewport as to which portion of the image
is currently being examined.  The navigator's viewport can be interacted
with using the keyboard or the mouse.

@memberof OpenSeadragon
@extends OpenSeadragon.Viewer
@extends OpenSeadragon.EventSource
@param {Object} options - Navigator options
@param {Element} [options.element] - An element to use for the navigator.
@param {String} [options.id] - Id of the element to use for the navigator. However, this is ignored if {@link options.element} is provided.