Cleanup database connection following command line installation

Previously lib.engine.final_cleanup was only triggered by the GUI.
This change results in the CLI also triggering a final cleanup
after installing a dataset.

This has the added benefit of allowing text file based output
formats to add any necessary end of file information.

__main__.py

@@ -112,6 +112,7 @@ def main():
                 print "=> Installing", dataset.name
                 try:
                     dataset.download(engine, debug=debug)
+                    dataset.engine.final_cleanup()
                 except KeyboardInterrupt:
                     pass
                 except Exception as e: