Merge concepts on Jacobian and GroupOfJacobian into GroupOfJacobian; the Jacobian concept was just a tool to implement the GroupOfJacobian and was never used as is, since ReferenceSpace::getJacobian is there ... with the introduction of Transformations, and to avoid confusion, the concept of Jacobian is therefore merged ... modifications seems to work (l2Projection tests and waveguide tests were OK)