post of what is GS ENG
Merge branch 'master' of https://github.com/genericsystem/genericsystem2011
modifying the check of SingularConstraint
modifying the check of singular constraint and writing the first post of
what is GS in english
sizeConstraintImpl
Merge branch 'master' of https://github.com/genericsystem/genericsystem2011
SingletonConstraint Test