support for password grant_type

[wireframe]

allow distribution of access token using Resource Owner Password Credentials as defined in the spec: http://tools.ietf.org/html/draft-ietf-oauth-v2-15#section-4.3

[jcoglan]

Fixed in https://github.com/songkick/oauth2-provider/commit/1b5ef123c9c0e89edf428eb326b417d883a98c24.

We're actually implementing draft 10, just so you know.