Add summary dialog summarizing the imported directory information

Now the database emits signals as various kinds of data are added.
These are matched to slots in the App Widget that track the information
and provide a summary dialog (optionally).

The test confirms that the signals and slots are properly tracking
the inserts.
Merge branch '221-instanceAdded-signal'

* 221-instanceAdded-signal:
  Add summary dialog summarizing the imported directory information