This pull request:

 - Allows admins to set their hackdays presentation_in_progress bool
 - Adds validations for hackdays (title/date)
 - Stops users from voting on their hacks
 - Adds a couple tests for the hackday controller

I experimented with different ways of stopping contributors from voting on their own hacks; ultimately, to keep it from showing up in the stream, I decided it made more sense to render a different view and create a flash warning via javascript. Obviously, if there is a different/better way you want this done, let me know.