I've just done a bit of refactoring so that the contents of the packages
are a little more cohesive and the names of the packages and classes now
refer to their contents, rather than just whatever I was thinking about
at the time I made them.
I've done a little more refactoring and I'll need to do something else
soon
I haven't really changed that much other than to rename accompaniment
generation as synth to reflect its more general purpose.