KalmanFilter: fix bug: you need to update the predicted state.

Signed-off-by: Jean-Yves Tinevez <jean-yves.tinevez@pasteur.fr>
Prevent bug when outputting the JaqmanLinker output.

Signed-off-by: Jean-Yves Tinevez <jean-yves.tinevez@pasteur.fr>
KalmanTracker: prevent bug when all costs are 0.

And offer to save predictions.
Signed-off-by: Jean-Yves Tinevez <jean-yves.tinevez@pasteur.fr>
An interactive test specific for the KalmanTracker.

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