[[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]]

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]]

[[Imported from SVN: r9990]]

[[Imported from SVN: r9980]]

[[Imported from SVN: r9979]]

[[Imported from SVN: r9978]]

[[Imported from SVN: r9977]]

This already saves a lot of disk space, because the class issues less whitespace
than our own code.  Plus, switching to binary data will be very easy now.

[[Imported from SVN: r9976]]

[[Imported from SVN: r9975]]

[[Imported from SVN: r9973]]

[[Imported from SVN: r9972]]

[[Imported from SVN: r9971]]

[[Imported from SVN: r9967]]

[[Imported from SVN: r9966]]

[[Imported from SVN: r9965]]

Previously, the number of multigrid transfer operators was always equal to
the number of grid levels minus one.  That worked out correctly when doing
first-order FE spaces.  However, for higher-order spaces, the up-most transfer
operator transfers from the higher-order space to a first-order space
_on the same grid level_.  But since the total number of transfer operators
was grid levels minus one, this implied that the coarsest grid leve 
was never used, and the coarse grid solver would operate on the second-coarsest
grid.

This patch adds the extra transfer operator in this case.  That means we now
call the coarse grid solver on smaller problems, which makes a noticeable
run-time difference.

[[Imported from SVN: r9964]]

[[Imported from SVN: r9963]]

Normally, the two different level grid views.  Previously we used the same one
to compute the localToGlobal renumbering for boths rows and columns.  Of course
that screws up the numbering.

I am not quite sure when that got introduced.  I may have gotten in fairly recently,
after the upstreaming of the GlobalIndexSet classs.

[[Imported from SVN: r9962]]

[[Imported from SVN: r9961]]

[[Imported from SVN: r9960]]

[[Imported from SVN: r9959]]

May happen when the matrix is singular.  UMFPack doesn't like that.

[[Imported from SVN: r9958]]

It tentatively uses the UMFPack direct solver, disregarding the obstacle.
If that leads to an energy-decreasing, admissible new iterate, then good.
Otherwise, it falls back to IPOpt.

[[Imported from SVN: r9957]]

[[Imported from SVN: r9956]]

[[Imported from SVN: r9955]]

[[Imported from SVN: r9954]]

Because it is not an index, it really is a mapper.

[[Imported from SVN: r9953]]

[[Imported from SVN: r9952]]

[[Imported from SVN: r9951]]

This is a first step towards having trust-regions with different scaling
in the different components.  Kinda paradox to introduce an explicit radius
in order to move away from a single radius.  But I want to pretend to
the outside (for the time being) that there is a single radius...

[[Imported from SVN: r9950]]

[[Imported from SVN: r9949]]

To really make sure I am doing the infamous L-shape example
like the people before me did I need point loads.  Being a
mathematician I am no particular fan of point loads, so they
may go out again eventually.

[[Imported from SVN: r9942]]

[[Imported from SVN: r9941]]

This is the interpolation method used by Ingo Münch and Wolfgang Müller for
Cosserat materials.  My implementation is only able to do all that I needed
for the illustrations in the GAMM Rundbrief article.  I'm sure there'll be
more fixes needed if you actually want to do finite elements with this.

[[Imported from SVN: r9940]]

For example, I'll use this for finite-strain elasticity problems.

Some of this should be in dune-fufem and/or dune-pdelab, but for the time
being it's easier to have it here.

[[Imported from SVN: r9939]]

[[Imported from SVN: r9938]]