[dune-functions] [dune-pdelab-commit] [branch] dune-pdelab - 'feature/new-functions-interface' updated

[Christian Engwer]

Dear all,

I have a running prototype implementation of a discrete function
implementing the envisioned dune-functions function interface.
Currently it only works for GFS leaf nodes and I doubt it would work
for non-scalar spaces.

I also implemented the general interpolate which allows to interpolate
a solution vector from dune-functions functions + some code to use
trees. This allows to do things like:
  Dune::PDELab::interpolate(
         [](const Domain& x) {return x[0];},
         p0gfs,x);

Please feel free to test ;-)

Ciao
Christian