Improve touch access for blind users

[willwade]

Currently to access Pasco via touch you have to click on the arrows on the screen, this approach doesn't really work for blind users, currently they would have to use an extra peripheral even if they don't usually need one.

We should allow users to make gestures to control Pasco so that they can control it using touch without needing to hit a specific target. There might be other ways to improve touch access for blink users.

CC: @michaelritson