fix compilation
add applyIMGeneral to _Q<> type in order to for the use of gauss point (not optimize quad point)
possibility to build reference element for topological face with several permutations.
not finish for hypercube shape.
store face quad points for each permutation of ref elt
up constructor (usefull for integrator)
update integrator (based on new quad face permutations) :
 -fix submesh<FACES> relation in 3d
 -fix integration of internal faces in 3d
add DCHECK
add Stokes example with dirichlet BC by using lagrange multiplier (work in //)