I discovered last night that the current implementation still only
partially addresses our original use case of acting as a minimum
aspect ratio for dialog buttons. If the default aspect ratio exceeds
the preferred value, the button height will grow, which isn't what we
want.
I think what we actually need are minimumAspectRatio and
maximumAspectRatio styles. If you set them both to the same value,
you'll get the current behavior. Otherwise, they act like bounds.
Unless there are any objections, I will modify the PushButton skin to
behave this way.
