Cleaned up list of GROMACS authors

Now the authors are listed alphabetically and in four neat columns
(only Berendsen's name overflows its allocated space, but that looks
OK).  List project leaders still separately at the end of the list.
Update the copyright year, add Stockholm University, and add some
contributors to the list of authors (found by digging git log and
including anyone with a full name and more than a few commits).

Change-Id: I14222bab394ee498380709fba9c0967e6d092980