Missing: buttonBorder

[dcporter]

In my use case, this view is nothing but a button. Our buttons are styled with borders, though, so the size of the button needs a way to get reduced by the layout border properties so that our button borders are visible.

If adding yet another buttonFoo property is repugnant then maybe buttonLayout instead? Consolidate height, width and border into one, and include developer warnings if someone tries to include inappropriate keys.