v1.0.1: Fixed a few issues

Problem: When the user is already added to persistence, and user signs in for the first time the dummy values in persistence were not getting updated.
Solution: Updating all the user details when the user signs in for the first time. When we fill the strategy vs id on the user object for the first time.

Problem: OauthToken constructor would throw Error when values are null, but null are usually expected for OauthToken
Solution: Updated the constructor to accept nulls too.

v1.0.0: Support for handling php login using any Oauth service you require.

* Interface for User and Session with it's respective services interface.
* Abstract classes for getting user-details from the OauthServiceProvider
* Strategy interface for implementing any oauth strategy.
* Default implementation for Oauth strategy where you can just pass the required url's and credentials for creating an oauth-strategy