Symmetric Pyramid + First derivatives as primary functions for first order complexes

[jmv2009]

Symmetric pyramid for Cockburn & Fu functions

Even though Cockburn and Fu https://arxiv.org/pdf/1605.00132 use asymmetric pyramids, the proposed functions are not easily orthogonal.

Furthermore, we need the derivatives of the functions in the 1-forms, and 2-forms. Here, they are explicitly included in the available function space.

Work in progress.