Random Patterns

[Chunky Kibbles]

Thanks to Aidan Burns, I've managed to implement random patterns.

Currently it doesn't do multiplex patterns, but everything you need to
create synchronous and asynchronous patterns is in jmlib. There's some
multiplex code there, but it tends to break, so you can't yet use it.

The only app that currently understands this is aajm, so if you want
to see this stuff in action, just crank up the current CVS of aajm and
hit 'r'.

Gary (-;

PS Also turns out that there's a bug in jmlib where a crossing zero
causes it to lock up. Which is nice.