This patch contains only whitespace changes.

Previously, some code was in Dune::GFE, some was in Dune::,
and a lot of it was in the global namespace.

I wrote them years ago mainly because I thought they should exist.
But they were never actually used them for anything, and I don't
really know were they could be used either.  Supposedly they
could be useful for implementing problems without a minimization
formulation, but that's not currently planned, and I don't know
what the precise requirements would be, either.

Since the code is short and almost trivial, and easily resurrected,
this commit removes the two files.  For newcomers this will mean
two less files to wonder about.

The old style has been deprecated for a long time, and is not
supported by dune-fufem anymore.

(In particular, the code discretizationerror.hh now requires
functions to satisfy the dune-functions function interface.)

In the wake of this, compute-disc-error.cc gets a number
of changes.  Let's hope I didn't screw up anything.

Using LocalIndexSet objects was mandatory with dune-functions-2.5
and earlier.  However, we only support 2.6 and later anyway,
so let's get rid of the backward-compatibility code.

Make them a parameter instead.  This allows to switch more easily between
geodesic finite elements and projected finite elements.

It is still no function in the dune-functions sense, but at least the
basis parameter needs to be a dune-functions basis now, rather than
a deprecated dune-fufem basis.

I intend to move as much towards the dune-functions interface for functions,
and this is a first step.

This implements a global GFE function (inheriting from VirtualGridViewFunction).
However, the return value of this function is _not_ a manifold class.  Rather,
the manifold is embedded into a Euclidean space.  Hence this class is formally
simply vector valued, and can be used in error measurement routines and such.

[[Imported from SVN: r10024]]

[[Imported from SVN: r8070]]

[[Imported from SVN: r8062]]

don't let the class inherit from gridfunction because there is no derivative type implemented for functions with values in manifolds

[[Imported from SVN: r7985]]

[[Imported from SVN: r7947]]

[[Imported from SVN: r7946]]

[[Imported from SVN: r7936]]

[[Imported from SVN: r7919]]

[[Imported from SVN: r7917]]

[[Imported from SVN: r7915]]

[[Imported from SVN: r7914]]