You can't have two mainpage items, and the second was just being
ignored. This restores them, which makes the left side list longer,
which we may or may not like, but it's at least how it was documented to
be.
New doc directory with config files and generated html, LaTeX/pdf.
Makefile provided for autogeneration and explanatory README.
The project structure is hostile to doxygen, which can't cope with functions
of the same name. Doxygen is run for each family separately, and separately
for LaTeX generation. Customized layout files sort of "integrate" HTML, and
separate pdfs are generated for each family. Not ideal but seems the best
solution until doxygen changes, if at all.
