Depend on TrackMate v2.5.0-SNAPSHOT for now.

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

We copied some of the TrackMate icons to MaMuT to loosen a bit the two
projects.
Signed-off-by: Jean-Yves Tinevez <jean-yves.tinevez@pasteur.fr>
Do not crash when semi-auto tracking missing data.

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