Add Presentations

[OxygenCobalt]

The frontend and backend for the presentations page.

Some notes:

• This contains some minor tweaks to the projects view, nothing that should affect functionality though.
• No author support for now until Ethan figures out the email issue.
• There seems to be some junk commits in this changeset from #37, I don't know how to get rid of those.
• Date functionality had to be updated to differentiate from plain dates with no time or duration, and datetimes and duration.