- Feature #205-#200-#249: Huge refactoring of node numbering and finite element handling: a proper RefFiniteEltFactory has been introduced, and it is way easier to introduce reference finite elements that aren't directly copied from geometry. For instance high order segments, quadrangles and hexahedra have been introduced in the Spectral class, which use a completely different numbering scheme (in which vertices and edges are intertwined). - Feature #247: Introduce Edge and Face orientation. - Support #98: Interface management has been refactored to be simpler and also more adaptive (a quality that will be required when adding orientation...) - Feature #243: Topology has been extended to provide functions such as IsOnEdge(), IsOnFace. Spectral finite element has been implemented and match Ondomatic's output. - Feature #236: Extend Topology classes to prepare high-order implementation. - Feature #225: Deep refactoring of FiniteElt management: now a FiniteElt and a FiniteEltType refers to only one Unknown; new objects FiniteEltGroup and FiniteEltTypeGroup are used when considering several Unknowns. Also better encapsulation, with fewer magic container to navigate through elementary matrices. - Feature #220: Clean-up of ElementaryData: improve its responsabilities (move matrices and vectors stored in FiniteElementType there) and avoid repeating the same tasks.