Update SQL to allow for multicontest: move the `cid` column from problem to a many-to-many table
Merge branch 'GEWIS' into multicontest

* GEWIS:
  Fix configuring
Update contest(s).php for the jury to allow for multiple contests
Problem page now supports multiple contests
Merge branch 'GEWIS' into multicontest

* GEWIS:
  Set judge dirs correctly as it does not work on the shared folder
Merge branch 'GEWIS' into multicontest

* GEWIS:
  Remove basedir as it breaks things
Multicontest: it should now work everywhere, but we still need a way to link teams to contests.
Allow to disable balloons per contest
Link teams and contests, so a team is not always part of every contest
Show submissions of all active contests, but allow to filter for only current contest
Fix refresh and store contest view state in cookie
Show contest ID in clarification subject
Now problems can be added to a contest on creation / edit
odd/even highlighted rows