Remove some wrong arguments.
PEP8.
Use utf-8 when exporting descriptions in ContestExporter (fixes #43).
Fix missing arguments in User and YamlImporter.
Make ScoreTypes convert the evaluation outcome to float

ScoringService should just consider it an opaque string.
Improve Job.export_to_dict and .import_from_dict
Fixes for SS when checking for submissions to be scored.

- for new_evaluation, check that the submission is really evaluated;
- use a set for submission_ids_to_* to avoid duplicated;
- do not add to it a submission not evaluated.
Fail gracefully if a wrong contest id is given as command line argument.
Simple ranking facility in AWS.
Referring to the released versions in the README.
Fix bug in UserTest importation
Make AWS accept a 'num' parameter when adding a Testcase
Make YamlReimporter keep user_tests, questions and messages
Restricted localization doc to !cmsranking.
Fix some internationalization issues
Another internationalization fix
Fail gracefully if RS is launched with a non-existent contest id.
More translations.
Suggestions and some bugfixes from pyflakes and pep8.
Mark another string as translatable