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]]