Added

An option request_debug_level on gocd.Server to set log level.
Set the session cookie when a request finishes if it hasn't been set.
This is intended to speed up subsequent requests to Go and will according to the documentation give a significant speed improvement for certain auth modules.
Pipeline groups API endpoint added.
This is used primarily now for getting a list of all available pipelines in gocd-cli and as such only has nice helpers for that use case.
Suggestions welcome for more useful wrappers here. :)

Fixed

Set the session cookie properly, Go will now not force another login after the session has been set