Fix uploading non-genbank files

- Issue a warning instead of an UD number when a user uploads something
  that is not a genbank file (fixes #59).
- Fix a Heisenbug in the batch job unit tests. Wait a little before
  downloading the batch job results.


git-svn-id: https://humgenprojects.lumc.nl/svn/mutalyzer/branches/refactor-mutalyzer-branch@365 eb6bd6ab-9ccd-42b9-aceb-e2899b4a52f1