optionally takes ?type=guilds (guilds, party, tavern, public). this
allows us to incrementally load the app as they click through the tabs,
because guilds is really large (1.5mb!) - gotta cut this down
somehow. The big issue is requireing return values as an array, so
ngResource can work with the response (subsequent group.$postChat(),
group.$join(), etc.). The array format doesn't really work out that
well, so I may scrap
