Hessians with blending for SUPG
This adds,
- Second derivatives (Hessians) of shape functions
- Affine and blending transformation for the Hessians
- Hessian of the blending map, directly calculated with
sp.diff
inGeometryMap
- Uses the blending substitution optimization from !3 (merged) for hessians of the blending map
- A test is also added under
hyteg_integration_tests
but as there were no previous forms to compare, a simple hand calculated math integration value is hard coded to compare