closes #367: Use PVL hideEdgeUI and showEdgeUI animations to perform y-axis translations on the AppBar element, instead of modifying element.style.top and element.style.bottom. This allows us to only have to reposition the "bottom" style attribute when the IHM shows/hdes, but never for AppBar animations.
closes #395: Introduce the win-appbar-minimal class to handle padding for invokebutton in and out of win reduced mode.