Release v2.2.0-rc4

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

Signed-off-by: Jean-Yves Tinevez <jean-yves.tinevez@pasteur.fr>
Add a constructor to FeatureFilter to facilitate scripting.

Signed-off-by: Jean-Yves Tinevez <jean-yves.tinevez@pasteur.fr>
En route for v2.2.0-rc5

Signed-off-by: Jean-Yves Tinevez <jean-yves.tinevez@pasteur.fr>
Fix bad generic bound with HyperSliceImgPlus.

Following #54 on imglib/imglib (HyperSliceImgPlus Improvements),
Christian completely rewrite HyperSliceImgPlus. This caused a minor
generic bound mismatch this commit fixes.
Signed-off-by: Jean-Yves Tinevez <jean-yves.tinevez@pasteur.fr>
Code style changes.

Signed-off-by: Jean-Yves Tinevez <jean-yves.tinevez@pasteur.fr>
Nicer filter panel look. Minor imrpovment.

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

Signed-off-by: Jean-Yves Tinevez <jean-yves.tinevez@pasteur.fr>
Fix bugs and NPE with spot coloring in the spot filtering stage.

Signed-off-by: Jean-Yves Tinevez <jean-yves.tinevez@pasteur.fr>
Merge remote-tracking branch 'origin/master' into manual-coloring
En route for v2.3.0

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