Fix sync leeway with tz-aware and tz-niave datetimes
Revising the last fix - Dropbox activities have no waypoints to determine TZ, so it'll be best-effort
Cleverness kills
Think these changes got lost in a merge, causing the sync worker to crash hard
Un-broke endomondo activity listing
Automatically kick off a sync when the user reconnects their account after a sync error (for re-auth, etc)