Nothing sophisticated but easier to debug certain tablet oddities.
It shows a bar for each axis on the tablet (and the evdev axis) and prints
that relative to the axis range. This makes it easy to check if we do hit the
full range (especially for distance/pressure/tilt) and whether that matches
with what the device gives us.
Signed-off-by: Peter Hutterer <peter.hutterer@who-t.net>
