Re-add import required for importing contests
Provide defaults for score_precision. (marginal improvement of UX)
Improve resilience and debugging in the face of failure.

Fixes a print in EvaluationService.py which would succeed if true, but throw an
exception on failure (because data["success"] is not valid, as data can be
None).
cmstestsuite: print stack trace on failure
Fixed bug that caused AWS errors when rescoring submissions
Fix AWS when viewing evaluated but not scored submissions.

If a submission has not been scored, s.score_details is not valid. The template
just needs to wait until they have been scored.
Remove unused get_encryption_alphabet from Cryptographics
Always log stdout/stderr somewhere.

If launched with /dev/null as our terminal, redirect stdout and stderr to our
logfile. Otherwise, useful information (e.g. backtraces on a crash) can be lost
forever.
Adding the new contributors to the AUTHOR file.