Really, really need pause. :-) This is tricky to do in an X-friendly
way, as it means keeping the display refresh going without moving
anything. Maybe just clear, stick up text saying it's paused, and not
bother with drawing the usual stuff while paused?


The source is a total mess, mainly because it was horribly Windowsy
originally and that hasn't really been fixed yet. May even want to
reindent the source to suit me, something I'd normally be very
reluctant to do - but I've hacked this *so* much it might be
justified.


X version is a bit flickery, and can be very flickery when the screen
is `busy' (leave it alone for a few minutes so swarmers take over, and
you should be able to see what I mean). Unfortunately, I don't think
there's too much I can do about this without killing the speed (I
found double-buffering noticeably slow), which is a pain.


It may be possible for (completely invisible!) black Spinners to be
created on level 16 or so. Need to check if that's the case and fix if
it is. (A proper fix would be a little bit more tricky than it sounds,
though. The color changes when hit, and is set in (at least) two
different places.)
