Adding Pyramid14 element.

Partial checklist for implementing new geometric element types:
* second_order_equivalent_type()
* n_second_order_adjacent_vertices()
* second_order_adjacent_vertex()
* Elem::build() case
* Elem::type_to_n_nodes_map
* Elem::type_to_n_sides_map
* Elem::type_to_n_edges_map
* first_order_equivalent_type()
* n_nodes()
Updating Makefile.am's
Ran boostrap.
Adding PYRAMID14 basis functions.
Adding first derivatives for PYRAMID14.
Adding second derivatives for PYRAMID14.
Add PYRAMID14 to all relevant branches in build_cube().

The actual work of converting to second order will be
done in the call to all_second_order().