Add 'reset' button

It's very tedious to deselect multiple XLFD field names if you want to
start from scratch (it's often easier to relaunch the app). Hence, a
simple reset button can be handy.

Signed-off-by: Alan Coopersmith <alan.coopersmith@oracle.com>
6 jobs for reset-button in 1 minute and 18 seconds (queued for 2 seconds)