cvs reorganized

I submitted the site request we discussed a couple of days ago to move
the users_guide and htdocs into the matplotlib CVS root. This makes
'cvs co matplotlib' much faster. I suggest you get fresh checkouts.
The three modules are

  cvs co matplotlib
  cvs co htdocs
  cvs co users_guide

I had asked them to rename htdocs and users_guide to mpl_htdocs and
mpl_users_guide but they overlooked this and I can live with it.

On a mildly related note, I just noticed that when I submitted the
site-request to have the matplotlib python tree moved into a lib
directory, all version history was lost. Damned cvs.