Allow uploading testcases archive in AWS
Wrapped the zipfile upload to catch bad zip files.
White spaces must be a bytes string.

Also, extend the set of white spaces with those defined by Unicode.
Typo in docs.
Fix pep8 warnings.
Simplify interface for java tasks.

Also add a fake updater to issue warning on the changed semantic of
the Java compilation.
Amend documentation for new languages.
Add tests for managed tasks in Java.
Add communication and managed functional tests for Pascal.
Don't allow contest.start and contest.stop to be null
Allow admins to limit the localizations of CWS available to users

Co-authored by Luca Wehrstedt.
Add interface for users to choose CWS localization, overriding browser

Co-authored by Luca Wehrstedt.
PEP8
Fixup
Fixup 2