RFU: doxygen 1.6.1-1

[Warren Young]

New upstream release:

wget -e robots=off --cut-dirs=2 -np -nH -A'*1.6.1-1*' -r \
    http://etr-usa.com/cygwin/doxygen/
setup.hint unchanged.

This is the first version packaged explicitly for 1.7.  Previous 1.5.5 
was copied over from 1.5 repo.