The driver solves the PDE given by the first form in forms. This is a
first step towards instationary problems.

The driver solves the PDE given by the first form in forms. This is a
first step towards instationary problems.

This reverts commit d0a87348.

NOTE: Works only for scalar equations

including CallInstructions for accumulation etc.

major remodelling of the DuneTarget

targetting better indexing logic.