Modified scope definitions and changed to use "expires_in_seconds"

From

http://openshift.github.io/documentation/rest_api/rest-api-1-6.html#authorization

The default scopes are

session - Equivalent of logging into an account with normal login credentials such as user name and password.
read - Access to the API is read-only, while authorization endpoints cannot be read.
userinfo - Only read access to the /user API resource is provided.

I know I confused things by having "sesson read" (which I think just means "session") in one of my unit tests.  I was just trying to see if they could be combined.  I added the scopes and a couple of unit tests to check permissions.  

Also, "expires_in" returns the expiration time that was originally set for the authorization.   "expires_in_seconds" returns the time remaining.  So I think we would want that one.

Thanks!