Added PartyManager that subclasses BetterManager, implements parties_during_range()
Agendas: add restriction of outer-joined mks to those associated with a party within the given ranges
Adding detailed roles - model, scraping and api #265

The member API currently have a 'roles' field that contains the current
role, to keep backward compatibility the new data was added under the
`detailed_roles` fields.
The new roles data is still not displayed on the MKs pages.
Fixed a bug when scraping gov roles
Agendas: bug fix - add coalesce so condition works for both sqlite and postgres + remove print
Scrape all relevent govs
reverting the APIv1 change and adding a note
Adding detailed_roles to APIv2 #265
Merge branch 'master' of github.com:daonb/Open-Knesset