Proj: Add project_interior_monomial_onto_side_face, which completes the implementation necessary for the method.
WGBasis: Add functions wgrad_for_mon_on_side_face, fe_inclusions_of_side_support, mon_num.
Meshes:
  - Moved RMesh2/3 and their tests into semi-trash folder.  Incorporate RMesh2 unit tests into RMesh's tests.
  - Reimplement integrals using proper face-specific origins where appropriate for monomials and polynomials.
  - Add nb_side_num field to NBSideInclusions structure, so it can usefully be returned directly from WGBasis.
  - Removed unnecessary integral function.
  - Renamed integral functions to make clear how mono/polynomials should be interpreted with respect to the origin for their inputs.
VBF/VBF_a_s: Finished VBF_a_s implementation (not yet tested).  Factored code that will be common to all var bf's into VBF module.