... while keeping compatible with dune 2.3

[[Imported from SVN: r10030]]

This is actually what is claimed in the paper.  Previously, the mirror
axis was y=0.005.  Having the grid symmetric across the x-axis itself
simplifies the expressions for the boundary conditions a little bit.

[[Imported from SVN: r10029]]

Kudos to Carsten Gräser for those new Python functions.

[[Imported from SVN: r10028]]

[[Imported from SVN: r10027]]

[[Imported from SVN: r10026]]

[[Imported from SVN: r10025]]

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]]

This is only a prototype, because the GFE solution function is replaced by
on where the interpolation is done in the embedding space.  That defeats the
purpose of measuring the GFE discretization error :-) but it is easier to
implement.  The real thing will follow shortly.

[[Imported from SVN: r10023]]

[[Imported from SVN: r10022]]

We can do it without the preprocessor.

[[Imported from SVN: r10021]]

I don't think I will need that again in the foreseeable future.
If ever it should be needed again the code can be taken from the
subversion archive.

[[Imported from SVN: r10020]]

The plan is to minimize the harmonic energy starting from the inverse
stereographic projection.  That projection already is the minimizer
of the energy, so it should be possible to measure convergence orders
against a known solution.

[[Imported from SVN: r10019]]

Do not fall back to 'harmonicmaps.parset' by default.

[[Imported from SVN: r10018]]

[[Imported from SVN: r10017]]

[[Imported from SVN: r10016]]

[[Imported from SVN: r10015]]

[[Imported from SVN: r10014]]

[[Imported from SVN: r10013]]

[[Imported from SVN: r10012]]

[[Imported from SVN: r10011]]

... so much difficult code obsolete now... AD rocks...

[[Imported from SVN: r10010]]

[[Imported from SVN: r10009]]

[[Imported from SVN: r10008]]

This is much more flexible and *much* easier to use.

Along the way, this patch scraps several old hard-coded Dirichlet boundary
values.  I don't even remember what they were good for.  If they are needed
again they should also be reimplemented in Python.

[[Imported from SVN: r10007]]

According to Christof Melcher, this produces a field of topological
charge q=1  (or -1, not sure).

[[Imported from SVN: r10006]]

[[Imported from SVN: r10005]]

[[Imported from SVN: r10004]]

[[Imported from SVN: r10003]]

[[Imported from SVN: r10002]]

[[Imported from SVN: r10001]]

[[Imported from SVN: r10000]]

[[Imported from SVN: r9999]]

[[Imported from SVN: r9998]]

[[Imported from SVN: r9997]]

Described in:
 Christof Melcher, "Chiral skyrmions in the plane", Proc. of the Royal Society, online DOI DOI: 10.1098/rspa.2014.0394

[[Imported from SVN: r9996]]

[[Imported from SVN: r9995]]

[[Imported from SVN: r9994]]

    
This removes a compiler deprecation warning.  By using the usual preprocessor magic
we retain compatibility with the dune 2.3 release.

[[Imported from SVN: r9993]]

[[Imported from SVN: r9992]]

There is no need to have our own implementation for this, we had it purely for
historical reasons.

Also, this change fixes a subtle bug:  Our own implementation used AlienElementLocalBasis,
which returns zero if the LocalBasis is evaluated outside of the reference element.
However, this happened sometimes due to rounding error on grids with very small quadrilateral
elements.

[[Imported from SVN: r9991]]