Add a Doxygen config file and a Makefile target 'doxy' or 'doxygen' which
-rw-r--r-- 17987 COPYING
-rw-r--r-- 3346 NEWS
-rw-r--r-- 2388 README
drwxr-xr-x - documentation
drwxr-xr-x - payloads
drwxr-xr-x - src
drwxr-xr-x - targets
drwxr-xr-x - util