Fixes for roll on reverse strand.

- Warning can also be shown for a roll on the reverse strand.
- Only the roll warning about the selected strand is shown.
- Roll of insertion where the inserted sequence changes now has correct
  description on the reverse strand.



git-svn-id: https://humgenprojects.lumc.nl/svn/mutalyzer/branches/refactor-mutalyzer-branch@275 eb6bd6ab-9ccd-42b9-aceb-e2899b4a52f1