up #354 : fix 3d mesh with order 3 and 4
the problem is due to a strange change in ho mesh generate by gmsh.
For an internal faces which is connected to elt0 and elt1, the geometric points contained in this faces (not vertex and edge) are
duplicate ( elt0 and elt1 are different with also a coordinate slightly differents ).
This correction change the geo point of elt1 by the elt0
add mesh functors
fix mesh straighten with extended elt