Initial work on adding notification support.  When the user syncs a vector layer, backup the old features to a temporary table, compute the notifications from the difference between the downloaded features and the old features, delete the temporary backup tables, save the notifications to the notifications table in the project db
Don't include the metadata when checking to see if the feature changed
Set up an activity for displaying the notifications, organized by syncs and layers.  The user can clear the notifications by feature, layer, or sync
When the user clicks on a feature notification, zoom to that feature if it exists in the local dbs, which translates to the feature still being on the map
Set up a badge to show how many notifications there are
Changed the way the badge gets updated after sync
Fixed a bug caused by a race condition in the layersLoader, and a bug caused by calling sync.startTileCache before initializing for the sync.  Should really refactor Sync.js so all dependencies are passed in