New Option for Blackberry keyboard devices: Partial Vertical Stretch

Stretches screen vertically by ~38% (midpoint of stretched and non-stretched).
Set this on by default for keyboard devices. Also set 'Show Touch' off by default.

Blackberry keyboard devices have a 1:1 aspect ratio (720x720 pixels).

The normal Stretch to Display setting does not suffice for these devices because the stretch from 408 -> 720 looks comical and very distorted.
So, I propose to meet mid-way at 564 where the stretch is not as obvious and yet it still takes up most of the screen.