Fixed strings

Had a rogue <br/> and a double-quoted string in there.
Allow managers to re-assess examples

This fixes a problem where managers were prevented from reassessing
their example submissions.
Fixed typo that broke upgrades

Accidentally had the wrong $oldversion in there. Also made this look
slightly nicer.
No groups in course bug fixed

Fixed a bug where, if there were no groups in a course, workshops
couldn't be instantiated.
IGNORE THIS

Rolled back from 2.3.3 to 2.3.2 to keep in line with Netspot's version
for testing. Ignore this commit.