Add gridGeometry.update(gridView)

In a recent update in dune the mappers got a new update(gridView) interface reflecting the value semantics of grid views introduced some time ago. In the same way we should also add gridView then to the gridgeometry.update function.

In our current usage it's slightly strange to write

GridGeometry gridGeometry(gridView);
gridGeometry.update(gridView);

So I suggest to change the behaviour of the grid geometry so that it already calls update in the constructor. We could add a special policy to be able to choose not initialize the grid geometry in the constructor if this is really needed.

As update gets a new signature, deprecation would be fairly easy I think if we accept that using the old interface update() means that you initialize the grid geometry twice (and you get a deprecation warning)