Every key copied the whole Im and Search rune by rune, compared them
after the transition, and combined the answer with 'eaten', a commit
count that is always zero, and a force flag for caret and owner changes,
while redraw() kept a separate 'visible' bit to know when to send an
empty popup. redraw() now compares the snapshot with the last one sent
and treats two empty popups as equal, so imhandlekey just ends in
redraw(). keystroke() was only a test entry point and moves there.
Hojun-Cho
68869e2589