- upgrade crossfire trt to the GPL version 3 (hopefully correctly).
- add a single file covered by the GNU Affero General Public License
  (which is not yet released, so I used the current draft, which is
  legally a bit wavy, but its likely better than nothing as it expresses
  direct intent by the authors, and we can upgrade as soon as it has been
  released).
  * this should ensure availability of source code for the server at least
    and hopefully also archetypes and maps even when modified versions
    are not being distributed, in accordance of section 13 of the agplv3.

Initial revision