Compatibility with new Oauth2 api authentication

  * Removed the last vestiges of the old REST Api.
  * Add Authorization: Bearer access_token header
  * Move some file, comment, etc operations to new api.
upload_version does not take a new_name, and takes the file to upload as the `name` parameter
Remove testing access token.

Developers are required to generate their own access token, which is now
outside the scope of this library.
Merge pull request #24 from peterkovacs/v2-oauth

Compatibility with new Oauth2 api authentication