cherry-pick commits to the release branch

6e21fb6 (Matthias Maier, 9 hours ago)
   step-34: Also adjust error message

cbe9f7c (Matthias Maier, 35 hours ago)
   CMake: Restructure configuration file

3a7c697 (Timo Heister, 2 days ago)
   wrapcomments on all files

240974e (Timo Heister, 2 days ago)
   manually reformat some files

d4eca17 (Timo Heister, 2 days ago)
   fix typo in step-52

3c2b85f (Timo Heister, 2 days ago)
   better @ref handling

   Correctly handle @ref in the wrapcomments.py script. We need to keep the
   description in quotes in one line and move everything else to the next line
   except immediate punctuation.