Social oauth

Not sure if you have already been working on this but it might be useful for inclusion if anyone wants social signups. I've added Twitter, Facebook and Google authentication as options within the Yeoman generator. If selected, authentication is set up within the express routing.

A loginOauth behavior is also added to the login controller to allow connections outside the angular routing. Method borrowed from https://github.com/fnakstad/angular-client-side-auth.

- Adding yeoman package options to choose which integration is required.
- Adding conditional routing to the social networks within express routes.
- Adding behavior to login to allow route connections outside the routes specified in angular routing.
- Adding login options to views for html and jade templates.