* Kindle FL shenanigans
Either fix#5986, or break a whole crapload of weird corner-cases.
Possibly the insane AutoFrontLight checks.
* Make fl step 0 usable on devices where 0 doesn't turn the light off.
By fudging an extra step on our own side.
* Also, add some debug logging around wmctrl to try to figure out what's
happening there...