To builk the matplotlib users guide, you will need to
* add the styles dir to your TEXINPUTS environment variable
* Generate the figures (png and eps) by running the script runall.py
in the code dir. Verify that the figures in the figures dir are
built. Verify also that the *.dat files in data were built. Or
run 'make figs'
* build the docs
> make dvi
> make pdf