ReadTheDocs is a site that can build documentation and serve it online
after every commit to a repository. We used to have something similar,
but it ceased to work at some point.
It looks like it's fairly simple to mate Doxygen with ReadTheDocs
(which uses the Sphinx documentation system) using a project called
Breathe.
http://breathe.readthedocs.org/en/latest/
I'll try to set this up for lib2geom tomorrow and report on the results.
Best regards, Krzysztof