Added sync manager called by refreshing groups
Added sync info properties to managed objects
Managed object create methods provide sensible defaults for sync info properties
Prevent two reloads when an empty group cell is edited
Handle table view update when a cell is deleted via the fetched results controller
Managed object deleted properties must be NSNumbers
Renamed sync property names and use toDelete key as predicate for group table
Implemented method to get JSON data for changed groups
Serialize device for syncing