Code style changes.

Signed-off-by: Jean-Yves Tinevez <jean-yves.tinevez@pasteur.fr>
Fix handling of the display settings in the Copy Overlay action.

The new panel configuring the display settings of the copied overlay was
not doing anything. You had to properly link it to a listener that is in
charge of updating the overlay look.

Signed-off-by: Jean-Yves Tinevez <jean-yves.tinevez@pasteur.fr>
Fix the TrackScheme and analysis button in the Copy Overlay action.

Signed-off-by: Jean-Yves Tinevez <jean-yves.tinevez@pasteur.fr>
Fix the copy to 3D viewer action of the Copy Overlay action.

Signed-off-by: Jean-Yves Tinevez <jean-yves.tinevez@pasteur.fr>