implement a function that takes a Model and returns the ufl forms that can be put into a scheme:

    scheme = galerkin( dune.femdg.femDGUFL(Model, space)[0] )
The function returns the [form,dirichletBCs] as first value as used above
and then the individual ufl models and additional terms extracted from the Model class, i.e.,
boundary fluxes, velocity, etc.

add test