swipe pattern StopIteration fixes

Signed-off-by: Paul Brook <paul@nowt.org>
Fix double buffering issues

Signed-off-by: Paul Brook <paul@nowt.org>

Conflicts:
	patterns/cubefill.py
	patterns/worm.py
Tweak worm pattern timing code.

Signed-off-by: Paul Brook <paul@nowt.org>
Tweak boxflip pattern timing code.

Signed-off-by: Paul Brook <paul@nowt.org>
Tweal fireworks pattern StopIteration logic

Signed-off-by: Paul Brook <paul@nowt.org>
temp
not really working at all
looking better
changes
added fade to red as the volume gets louder
dunno
make audioblob more VU-like
Added frequency spectrum. Unfinished
Nice VU colours
Fade historical spectrums out
Commented-out code allowing slowing down of history
Tidying up