Expose signal so users of app widget know about directory imports

Allows users of the widget to process the data after it
has been imported.

Libs/DICOM/Widgets/ctkDICOMAppWidget.cpp

@@ -448,10 +448,15 @@ void ctkDICOMAppWidget::onImportDirectory(QString directory)
     connect(d->DICOMIndexer.data(), SIGNAL(progress(int)),
             this, SLOT(onProgress(int)));
 
+    // close the dialog
     connect(d->DICOMIndexer.data(), SIGNAL(indexingComplete()),
             progress, SLOT(close()));
+    // reset the database to show new data
     connect(d->DICOMIndexer.data(), SIGNAL(indexingComplete()),
             &d->DICOMModel, SLOT(reset()));
+    // allow users of this widget to know that the process has finished
+    connect(d->DICOMIndexer.data(), SIGNAL(indexingComplete()),
+            this, SIGNAL(directoryImported()));
 
     d->DICOMIndexer->addDirectory(*d->DICOMDatabase,directory,targetDirectory);
   }

Libs/DICOM/Widgets/ctkDICOMAppWidget.h

@@ -70,6 +70,8 @@ Q_SIGNALS:
   void databaseDirectoryChanged(const QString&);
   /// Emited when query/retrieve operation has happened
   void queryRetrieveFinished();
+  /// Emited when the directory import operation has completed
+  void directoryImported();
 
 protected:
     QScopedPointer<ctkDICOMAppWidgetPrivate> d_ptr;