Spot: enforce the specification of x, y, z, radius and quality.

So that we never have a spot missing critical features.
Signed-off-by: Jean-Yves Tinevez <jean-yves.tinevez@pasteur.fr>
Ignore by-products of the fiji pom.xml.

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