majalan

Copperbox revision 2857.

I've added a couple more GENs - GEN01 which loads a file and GEN02 which stores user supplied data.

GEN01 particularly is an interesting case - should Majalan imitate Csound (e.g. use numeric enums rather than enum types) or provide a higher level (but not idiomatic) API? At the moment imitating Csound seems a better choice as GENs are usually invoked only a few times in a score and following the Csound means its documentation is mostly appropriate.