Update normalize.pl to also substitute 8.2.pre version
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.
fix doxygen warnings
Merge pull request #349 from tamiko/dealii-8.2

Cherry-pick commits to the release branch