Provide account management helpers

[mario]

Things like registration, login, forgotten password and change password would be awesome to have.

[nicolaiarocci]

While in theory this stuff could be handled via API, it is usually handled out-of-band for a few good reasons, namely security and REST contraints (RESTful = stateless, so there's no 'login' concept to be applied here: each request must provide auth data if the API is protected). Best practice would be to provide a web interface for registering, retrieving password/HMAC signatures, etc.