Swithc a lot of examples

...sson/dimension-grid-variations/poisson_1d_cg_interval.ufl

...sson/dimension-grid-variations/poisson_1d_dg_interval.ufl

...dimension-grid-variations/poisson_2d_cg_quadrilateral.ufl

...sson/dimension-grid-variations/poisson_2d_cg_triangle.ufl

...dimension-grid-variations/poisson_2d_dg_quadrilateral.ufl

...sson/dimension-grid-variations/poisson_2d_dg_triangle.ufl

...on/dimension-grid-variations/poisson_3d_cg_hexahedron.ufl

...n/dimension-grid-variations/poisson_3d_cg_tetrahedron.ufl

...on/dimension-grid-variations/poisson_3d_dg_hexahedron.ufl

...n/dimension-grid-variations/poisson_3d_dg_tetrahedron.ufl

test/poisson/poisson_dg_neumann.ufl

test/poisson/poisson_dg_quadrilateral.ufl