Code style changes.

Signed-off-by: Jean-Yves Tinevez <jean-yves.tinevez@pasteur.fr>
Allow the 3D viewer to properly deal with new content.

Before this commit, the 3D viewer would crash when manually adding a
spot or an edge to a previously empty frame.

Signed-off-by: Jean-Yves Tinevez <jean-yves.tinevez@pasteur.fr>
Fix various bugs with coloring.

- Some color generators were de-registered in a bad way.
-The addition of new spot does not seem to work well.

Signed-off-by: Jean-Yves Tinevez <jean-yves.tinevez@pasteur.fr>
Merge branch 'master' of github.com:fiji/TrackMate