Refactored so that the widget is now with the app, not the provider

 - CalendarAppWidgetReceiver now functions as the broadcast receiver for:
     * android.intent.action.TIMEZONE_CHANGED
     * android.intent.action.TIME_SET
     * android.intent.action.PROVIDER_CHANGED (content://com.android.calendar)
 - CalendarAppWidgetService has been refactored to use IntentService for
   serializing widget updates
 - AppWidgetShared has been preserved for managing wake locks
 - CalendarAppWidgetModel was pulled out into its own class

Change-Id: If7641aba278acc8ad00f14acd289ddbcbb1d5bcf
Merge commit 'bb3f08abac01e3083d837e5e823b311e3c039e90' into oxygen_1006

* commit 'bb3f08abac01e3083d837e5e823b311e3c039e90':
  Refactored so that the widget is now with the app, not the provider