#33 Structure: Better management of discharge inversion. PAB tests are better for discharge calculation but still wrong.

Merge branch '33-ajout-du-calcul-d-une-passe-a-bassin' of gitlab-ssh.irstea.fr:david.dorchies/jalhyd into 33-ajout-du-calcul-d-une-passe-a-bassin

refactored PAB for late model binding

only write to currentValue during calculation
Fix incorrect use of isDefined in SectionCirc
isDefined: protection against empty result
.v is now held by ParamDefinition and not ParamValues
updated tests
adapted value mode checks to new local .v

refactored PAB for late model binding