[MWF] Display visual feedback on pressed button

When a button is pressed the image and the text needs to be rendered one
pixel to the right and to the bottom so that there is some visual
feedback of the button press. Previously this was only the case if
TextImageRelation was set to Overlay.

This fixes Xamarin-23869

Change-Id: Icb38d7708f06d5b53be4f9e294b10e963f1b5b3b