When cloning BB track, indicate this fact in name of cloned BB track

Cloning a BB track can be rather confusing (e.g. two "Beat/Bassline 0").
Therefore prepend an indication to the name of the cloned BB track.
(cherry picked from commit 3b642271a8)

src/tracks/bb_track.cpp

@@ -472,6 +472,8 @@ void bbTrack::loadTrackSpecificSettings( const QDomElement & _this )
 			// and move back to where it belongs!
 			d->movePosition( pos );
 		}
+		setName( tr( "Clone of %1" ).arg(
+					_this.parentNode().toElement().attribute( "name" ) ) );
 	}
 	else
 	{