This is needed to actually compare the 3D-model with the 2D-approximation

Deprecate the call to energy with a RigidBodyMotion in cosseratenergystiffness and in nonplanarcosseratenergystiffness - this is actually duplicate code!

They can't be removed yet because they are still used in tests though!

Correct the sign of the Neumann and volume forces to make it consistent throughout dune-gfe and dune-elasticity

In the energy file, the energies are *added*.
The Neumann and volume forces get the correct sign in the actual program file by mulitplying with (-homotopyParameter).

ADOL-C implements most standard math functions for its
'adouble' type, and they are not in the namespace 'std'.
dune-fufem contains a file adolcnamespaceinjections.hh
which imports some of these methods into the 'std'
namespace, but that is not the proper way to do it.
Rather, they should be found by argument-dependent
lookup (ADL), that is

  using std::sin;
  auto v = sin(x);

Virtual Function is deprecated after dune 2.7.

Also adjust CosseratEnergyStiffness and MixedGFEAssembler for the use with a CompositeBasis instead of a PowerBasis

Several energy density implementations contained code for matrix methods
like sym, skew, transpose etc.  This patch moves them all to the file
linearalgebra.hh, to get rid of the redundancy.

Because it really is a functionality of rotation matrices in quaternion
representation.  Only the Cosserat energies use it at the moment, but
this is coincidental.

In the same process, the method is renamed to quaternionTangentToMatrixTangent.
That seems to be a more telling name.

Previously, they all inherited from LocalGeodesicFEStiffness,
which was weird, because none of them implemented first or
second derivatives as you would expect from something called
'stiffness'.

It's the same code, but the old name is deprecated.

Introduce preprocessor variable PROJECTED_INTERPOLATION to switch between geodesic FE and projection-based FE

This is a temporary solution; we need something smarter eventually.

Because these two classes are for the most part identical.

Currently, this merged version involves some trickery, including some template
specializations and multiple inheritances.  I hope to get rid of that, eventually.

This is how the new dune-functions bases should be used.  Also, it is yet
another step towards merging CosseratEnergyLocalStiffness and MixedCosseratEnergy.

The DR variable (the derivative of the microrotation R wrt space) had dimensions 3x3x3.
This is two big in a shell context, because there are actually only two space dimensions.
Hence the correct size is 3x3xgridDim.

The results without this patch were not wrong, though, only a bit wasteful.

Getting intersections from the element has been deprecated for a long time,
because the precise intersection one gets does not only depend on the element,
but also on the grid view.

[[Imported from SVN: r10090]]

[[Imported from SVN: r10088]]

[[Imported from SVN: r9949]]

This form allows to set the shear correction factor kappa.  It is still
not ruled out that we need to twiddle with this factor in order to
weaken the material a little bit.

[[Imported from SVN: r9937]]

This bug has now influence as long as mu_c is zero, but for
non-zero mu_c there was one term missing.

[[Imported from SVN: r9865]]

[[Imported from SVN: r9785]]

The CosseratStrain object is a 3x3 matrix, where the last column
is (0,0,1)^T.  This special structure allows to use specially tuned
matrix methods (e.g., the determinant), which I intent to do in the
future.

[[Imported from SVN: r9752]]

This move more than halfs the size of this file, and makes it *much* easier
to understand.  If we ever need the gradient code we can still recover it
from the 2.3-2 branch.

[[Imported from SVN: r9650]]

It used to be a compile-term error, but now that we have ADOL-C support
the missing gradient is not a problem anymore.

[[Imported from SVN: r9516]]

This patch brings it back.

[[Imported from SVN: r9477]]

[[Imported from SVN: r9402]]

The only exception is the material parameters.  ADOL-C (for which
we are doing this), doesn't need to have them in a special type.

[[Imported from SVN: r9401]]

Saves us one call to sqrt().

[[Imported from SVN: r9400]]

[[Imported from SVN: r9389]]

[[Imported from SVN: r9388]]