Reorganize the file `AUTHOR', according to the current status of copyright

Reorganize the file `AUTHOR', according to the current status of copyright
assignments received by the FSF.

Jason Thomas was added.
Erich Stefan Boleyn was moved into those who assigned their copyrights.
Gordon Matzigkeit was moved into the others, because he still wasn't listed
in fencepost.gnu.org:/gd/gnuorg/copyright.list.

The remaining problem is that we haven't had copyright assignments of
VaX#8, Heiko Schroeder and Gordon Matzigkeit. As for the first two, Erich
is now trying to contact them by proxy. So I'm just waiting.

As for Gordon.... oh, what are you doing, Gordon?! Hurry up, please!