Add passport local auth
Implement a lot of passport.js authentification stuff.
Implement more of the OAuth 2.0 specifications
Clean up code.
Remove anything related to sessions

Using sessions is a violation of REST principles. Since this
is going to be a RESTful api, it should be stateless.
Merge branch 'oauth'

Implement OAuth2.0 authentification. Currently, the only grant_type
that works is password as that is the grant_type that the web app
will be using.