Add basic infrastructure for pitches.
Add detail view for pitches.
Basic support for Google OAuth 2.
Basic Google Drive integration.

- You can list Google Drive files and import the contents of a text
  document into the current pitch.
- Currently all the Google Drive API calls are done from the webserver,
  so there's an extra round-trip to list the contents of your drive.
  Next step is to learn how to use the Javascript SDK to this stuff
  client-side.