We were carrying old copy of sphinx extensions.  They are now all in
Debian stable (squeeze) which is soon to be replaced by Debian Wheezy,
so time to drop the old extension code.

Switch from matplotib 'htmlonly' directive to sphinx's own 'only'
directive.

Causing warning in sphinx build

There was a stray "plots" and there were several ".. plot :: "
statements.

Update to changes in use of symbolic HRFs.
Turn of 'usetex' for matplotlib; matplotlib handles the TeX in the plots
fine with its own renderer.
Add comments and change imports to more canonical form.

We had a lot of information in the INSTALL file in the root directory of
the project.  Now we're releasing, this should go in the docs instead.

We were pointing to the INSTALL page, that's now gone.

Fill out stuff about temporary files.

The registration documentation was also out of date - removed.

Moving parts of coordinate map discussion into separate files.

Rewrite the examples in doctest format.  Make them match the current
approved API.

Add description to try and put people off reading most of these
documents.