moveoff_gui: option for -noentry

-noentry: don't create numeric entry
          (display increment +/- buttons only)

also: popup for WM_DELETE_WINDOW when allowed
+whitepace

Signed-off-by: Dewey Garrett <dgarrett@panix.com>
moveoff.comp: provide waypoint-percent-used pin

and display in gui when threshold exceeded

Signed-off-by: Dewey Garrett <dgarrett@panix.com>
moveoff_gui: replace zero button with per axis 0

Signed-off-by: Dewey Garrett <dgarrett@panix.com>