[fluxus] livecode recorder

[dave]

I've put back the live code recorder, for recording and replaying
keypresses and mouse actions. This is now much easier to use than
before, as it's all controlled via flags to the scratchpad, rather than
confusing F key combinations:

fluxus-0.13 -r filename : record to file
fluxus-0.13 -p filename : playback from file
fluxus-0.13 -p filename -d time : seconds per frame time override for
playback (for use with frame-dump)

It might be an idea to use these files for distributing tutorial walk
throughs - a lot smaller than videos...

I also forgot to mention (hint-cast-shadow) for use on objects you want
to generate shadow volumes for, and I've also added
example/28-shadows.scm 

cheers,

dave