wumpus-clave - now wumpus-rhythm!

Copperbox revisions 1937 - 1940.

Wumpus-Clave has now become Wumpus-Rhythm.

Originally Wumpus-Clave supported drawing clave patterns in the Box notation. However that code is obsolete and the only working code is for djembe patterns. Rather than have a Wumpus project for every notation, it seems better just to have them all under a large enough name / category - "rhythm".

I had finger trouble with Subversion hence the four commits. Accidentally I deleted wumpus-rhythm just after I added it (wanting to delete wumpus-clave) however I couldn't seem to undo the delete (resolving to theirs-full wasn't resolving to the repository). In the end I deleted the newly added files and added them again, not ideal.