Cherry-pick commits to the release branch

6ce052d (Timo Heister, 10 minutes ago)
   fix doxygen warnings

24f42c1 (Matthias Maier, 7 hours ago)
   try to get the arpack test a bit more stable

   Well, it turns out that depending on arpack version and CPU the result for
   the first 5 eigenvalues differs. Try to make this a bit more stable by
   computing 8 eigenvalues and only print the first 5.

0c815a4 (Matthias Maier, 28 minutes ago)
   Update normalize.pl to also substitute 8.2.pre version