Style revamp
Update reveal submodule to 2.5.0
Put a skip button at the start.
Minor tidy up and commenting.
Show solutions count and slide nav on results screen
Remove extraneous slides
Additional style updates.
Add a Vagrant setup
Ignore vagrant stuff
Merge branch 'revamp'

* revamp:
  Additional style updates.
  Remove extraneous slides
  Show solutions count and slide nav on results screen
  Minor tidy up and commenting.
  Put a skip button at the start.
  Update reveal submodule to 2.5.0
  Style revamp