This implements a global GFE function (inheriting from VirtualGridViewFunction).
However, the return value of this function is _not_ a manifold class.  Rather,
the manifold is embedded into a Euclidean space.  Hence this class is formally
simply vector valued, and can be used in error measurement routines and such.

[[Imported from SVN: r10024]]

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]]

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: r9927]]

[[Imported from SVN: r9897]]

[[Imported from SVN: r9891]]

This used to be in the base class as default implementations, but I think
it is nicer to have it in a derived class.  In particular, this will
eventually allow to do the FD approximation with high-precision number types.

[[Imported from SVN: r9842]]

[[Imported from SVN: r9682]]

[[Imported from SVN: r9394]]

This is just an initial commit.  It is a copy of the corresponding code for
unit vectors, with just a few names exchanged.  The actual functionality
will come in subsequent commits.

[[Imported from SVN: r9076]]

[[Imported from SVN: r8630]]

[[Imported from SVN: r8629]]

[[Imported from SVN: r8554]]

from a Pk-basis to a P1-basis.

Doesn't work beyond P2 yet, I'll fix that in a second.

Should eventually go into dune-solvers.

[[Imported from SVN: r8218]]

[[Imported from SVN: r7966]]

[[Imported from SVN: r7955]]

[[Imported from SVN: r7924]]

[[Imported from SVN: r7921]]

[[Imported from SVN: r7899]]

And use it to implement the Rotation<3> class.  This makes the
Rotation implementation easier to understand.  Previously we
have used a FieldVector<3> when a skew matrix was meant.
This leads to confusion now that we also use quaternions as
tangent vectors of SO(3).  In local coordinates, these also
have 3 entries.  Adding the new skew matrix class makes it
clearer what kind of mathematical object is meant.

[[Imported from SVN: r7897]]

[[Imported from SVN: r7547]]

[[Imported from SVN: r6743]]

[[Imported from SVN: r6722]]

[[Imported from SVN: r6721]]

This class should centralize some of the logistics needed for the knee
models and similar stuff.  Eventually, domain decomposition solvers should
be able to work on this data structure.  That is still a way off, though.

[[Imported from SVN: r6716]]

[[Imported from SVN: r6715]]

[[Imported from SVN: r6714]]

[[Imported from SVN: r6046]]

[[Imported from SVN: r5936]]

[[Imported from SVN: r5931]]

globally refine a grid and transfer a given function to the next level.  Works for all TargetSpaces and replace rodRefine, which did the same only for RigidBodyMotions

[[Imported from SVN: r5771]]

[[Imported from SVN: r5636]]

[[Imported from SVN: r5560]]

[[Imported from SVN: r5323]]