[[Imported from SVN: r7867]]

[[Imported from SVN: r7842]]

[[Imported from SVN: r7611]]

[[Imported from SVN: r7567]]

[[Imported from SVN: r7566]]

coordinates into a separate method, and fix an index bug on the way.
Now this derivative passes an fd check.

[[Imported from SVN: r7565]]

[[Imported from SVN: r7564]]

[[Imported from SVN: r7560]]

[[Imported from SVN: r7559]]

[[Imported from SVN: r7558]]

[[Imported from SVN: r7557]]

[[Imported from SVN: r7556]]

[[Imported from SVN: r7555]]

and barycentric coordinates.  This is easy because we know the
number of element corners at compile time (I currently don't
see support for non-simplex elements at all).  This saves 
time, but not much: about 1%.

[[Imported from SVN: r7550]]

[[Imported from SVN: r7543]]

[[Imported from SVN: r7423]]

remove the TargetSpace parameter of the Cosserat energy class -- Cosserat materials only make sense with RigidBodyMotion values

[[Imported from SVN: r7418]]

It will implement the energy of the elastic Cosserat modell
for continua and shells proposed by Patrizio Neff.  So far
it is only a copy of the harmonic energy, though.

[[Imported from SVN: r7417]]