With this, the preparatory stretching experiment for film-on-substrate can be done using dune-gfe.
The vertices for adaptive refinement can now be selected without specifying a shell area.

Change the keywords for switching between the solvers to trustRegion and proximalNewton also in film-on-substrate

This is currently the faster solver

Add option to read in a displacement file that will be used for the stress-free configuration of the shell elements
When startFromFile is set to true, then the stress-free configuration is read from the given file - this file needs to match the *finest* level of the grid
When startFromFile is set to false, the stress-free configuration can be given in as a function

Added program to solve a combined minimization problem:
Minmize the sum of an elastic energy (representing the substrate)
and a cosserat energy (representing a thin film on the substrate).

Good to measure whether there is locking, and whether the code works
at all.

[[Imported from SVN: r9997]]

[[Imported from SVN: r9801]]

[[Imported from SVN: r9800]]

[[Imported from SVN: r9799]]

[[Imported from SVN: r9797]]

That way, we can now control what vertices are Dirichlet and Neumann without having
to recompile the code.

[[Imported from SVN: r9794]]

[[Imported from SVN: r9788]]

[[Imported from SVN: r9784]]

[[Imported from SVN: r9781]]

[[Imported from SVN: r9692]]

[[Imported from SVN: r9668]]

[[Imported from SVN: r9658]]

[[Imported from SVN: r9545]]

[[Imported from SVN: r9291]]

[[Imported from SVN: r9275]]

- set mu_c to 0
- introduce the shear correction factor 'kappa'

[[Imported from SVN: r8328]]

[[Imported from SVN: r8327]]

[[Imported from SVN: r8326]]

[[Imported from SVN: r7546]]

[[Imported from SVN: r7432]]

using the ideas of Patrizio Neff.

In particular, this code should handle real 3d continua, as well
as Neff-style Cosserat shells.

This initial commit only adds a lot of infrastructure.

[[Imported from SVN: r7339]]

[[Imported from SVN: r5726]]