Doxygen + Autotools integration

Hi all,

My name is Stefano and I'm the author of NASPRO (http://naspro.atheme.org).

I've been playing a bit lately trying to write support for Doxygen on
Autoconf/Automake and here I am to give you the results of my work.

I am not an expert of m4, shell, make, autoconf or automake, so it's
very very likely that what I've done need a lot more love from someone
with more expertise than me, but nonetheless what I've done works
quite well for me (unlikle the doxample thing) and could be a good
starting point.

Attached are the configure.ac, Makefile.am and Doxyfile.in files used.

For anything I'm here... let me know,

Stefano D'Angelo