Saner errors for adding a testcase in AWS.
Improve internationalization of CWS
Adjusted the severity of the log messages.

Also:
- removed some unused imports;

- removed the reference to the local copy when informing a contestant
  that its submission did not went through;

- added some infos on the logs in the README;

- slightly rephrased some error messages.
Make RS do its restarting things even when not installed.
Rename 'usertest' to 'user_test' in CWS, too
PEP8-ify the WebServers
Start providing some documentation using Sphinx
Improve documentation for RWS