UX: improve messaging so notifications list is far more stable
PERF: improve performance of notifcation lookup queries
- Add feature "SetTransientHeader" that allows shipping info to server
in the next Ajax request
- remove local storage hack used for notifications
- amend lookupStale to return hydrated objects, move logic into store
- stop magically clearing various notifications (likes, invitee accepted, group_summary, granted badge)
Sam