Improved the documentation building script.

The script now generates all module documentation, and then runs Sphinx, and
finally opens the docs in a webbrowser if the build format was "html".

Invoke it like this:

    documentation$ python ./make.py ``buildFormat``

... where ``buildFormat`` is "html", "latex" or "latexpdf".

TODO:

Test LaTeX output, implement a "clean" option, and test the doc building
process on Windows.


git-svn-id: http://music21.googlecode.com/svn/trunk@3496 5c16147e-a200-11de-b0cc-ab0ad15e60d0