* Provides a basic Overlay widget, with Standard Module content support. The Overlay widget
                             * provides Page XY positioning support, alignment and centering support along with basic
                             * stackable support (z-index and shimming).
                             * @module overlay
                             * A basic Overlay Widget, which can be positioned based on Page XY co-ordinates and is stackable (z-index support).
                             * It also provides alignment and centering support and uses a standard module format for it's content, with header,
                             * body and footer section support.
                             * @class Overlay
                             * @constructor
                             * @extends Widget
                             * @uses WidgetStdMod
                             * @uses WidgetPosition
                             * @uses WidgetStack
                             * @uses WidgetPositionAlign
                             * @uses WidgetPositionConstrain
                             * @param {Object} object The user configuration for the instance.
                            Y.Overlay = Y.Base.create("overlay", Y.Widget, [Y.WidgetStdMod, Y.WidgetPosition, Y.WidgetStack, Y.WidgetPositionAlign, Y.WidgetPositionConstrain]);