Improve action on manual Keypad when activated from the keyboard.

[tedh-shopbot]

This PR improves the visuals of using the Keypad from a keyboard and specifically makes the axis button illumination work the same as with a mouse for short nudges and longer holds. Issue #1058

It also adds the keyboard shortcuts suggested in Issue #1067 (toggle fixed; ">" for changing speed) including an exit by clicking anywhere outside modal keypad.

Having played with these, we might want to additionally consider the following shortcuts:

• XYZ keys could select one of the location entry windows for data entry. Once in that selected state:
  • ctl-Z could zero the axis (ctl to make sure you really want to zero)
  • G could start the Go To behavior
  • S could do the Set To behavior
• We could also consider a typematic feature in the fixed mode where holding down long enough would start a repetitive fixed move pattern of punctuated small moves
• And, we could consider enabling the Mouse-as-Remote-Pendant per the way Sb3 works

Tested with sb_logo and the SK insert of dev-tests.
Checked appearance on mobile.

I've done some keypadding around on the two tools I have. There are the occasional responsiveness irregularities in using the keypad with happy-fingers (not always triggering, or triggering more than intended). I don't think this has changed. This includes the occasional longer-than-intended move. We may want to keep our eyes out for methods to duplicate these and clean Keypadding up some more.

Note that this is extension to ongoing work and PR's. It is the last 3 commits.

[kyle-kingsbury]

Ran the dev-checks and a couple of cut files. Tested the keypad extensively: goto, set, fixed moves, continuous moves, zeroing axes, adjusting move speed with new hotkey, entered fixed mode with new hotkey, tested all with keyboard and mouse. Everything seems to work well.