Enable Gauss-Legendre integration rules for second-order finite element
Gauss-Legendre integration rules implemented, but it is possible to use them only for linear elements. Here, GL rules are enabled for Tri2, Quad2, Tet2, Hexa2. It is also enabled for LinePrism/Pyramid/1/2, but Gauss is used by default.
Tested with Quad2 => OK.
Edited by Axel Modave