Improve regularization options

[ytanguy]

The last PR (analyse vegetation clustering) opened new ways of regularization.
Several other options have to be tested / implemented :

• regularize high vegetation and shadows / low vegetation : a (small) area marked as shadow (or low veg) included in high vegetation should be marked as high vegetation
• try to regularize WSF (instead of the urban probability mask) with other classes (shadow, bare ground, void) and give priority to vegetation and water areas.