More for sreview

More for sreview

Wouter writes:
- The sreview-notify script unconditionally loads Email::Simple and
  Email::Sender, even though (for DebConf) we end up not using them.
  Rather than commenting out the "use" lines in the perl scripts, it
  makes more sense to install the packages so we can run from a git
  checkout that isn't modified
- For the dc18 open/closing slides, we need a few extra fonts installed,
  otherwise things look wrong. Do so.