Party members order

This feature adds a select input in `Social → Party → Members`, to allow users to sort the party members by level, random, number of pets, or party date joined (the current sorting).

Need to review the design, maybe the select isn't in the right place.

Also note that I couldn't add the **partyOrderChoices** dictionary in `HeaderCtrl` (something about $scope.party.members raising an error at that moment). Maybe it would better fit in PartyCtrl though.