This triggers bugs in the Rotation and RigidBodyMotion classes.

In particular, it triggers what Jonathan Youett fixed in the
never-merged merge request

  !2

These bugs are fixed in this commit, too:
* The RigidBodyMotion class gets a `log` method
* The Rotation<3>::log method now returns EmbeddedTangentVector
  instead of TangentVector.

This involves fixing the secondDerivativeOfDistanceSquaredWRTSecondArgument
method: Previously it returned a FieldMatrix, but the test requires
a SymmetricMatrix.

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.

That projection is the zero map, not the identity.

[[Imported from SVN: r9843]]

[[Imported from SVN: r9648]]

[[Imported from SVN: r9449]]

I can't make up my mind whether I want 'ctype' or 'field_type'

[[Imported from SVN: r9447]]

When using the classes with ADOL-C, T becomes an 'adouble',
which is a non-trivial type.  However, the convexityField
is constexpr (and with a reason -- otherwise we could write
the initialization together with the declaration), and
constexpr and non-trivial types don't work together.

[[Imported from SVN: r9444]]

This is needed to use the ADOL-C automatic differentiation library.

[[Imported from SVN: r9398]]

[[Imported from SVN: r9397]]

And use it in the test.

This patch uses the new 'constexpr' macro.  Hence it is C++11 only.

[[Imported from SVN: r9195]]

It makes it difficult to be sure that an explicitly
requested type is really handed over to every place.

While we are at it: reverse the order of the template
parameters.  Now first comes the type, then the dimension.
This is more like FieldVector and friends, and hence
should be less confusing.

[[Imported from SVN: r8148]]

[[Imported from SVN: r8146]]

needed to make the targetspacetest.cc test case pass.

[[Imported from SVN: r8041]]

[[Imported from SVN: r8040]]

[[Imported from SVN: r8039]]

[[Imported from SVN: r7991]]

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: r7611]]

[[Imported from SVN: r7573]]

[[Imported from SVN: r7427]]

[[Imported from SVN: r7415]]

[[Imported from SVN: r7374]]

[[Imported from SVN: r7342]]

[[Imported from SVN: r6750]]

[[Imported from SVN: r6748]]

[[Imported from SVN: r6708]]

[[Imported from SVN: r6707]]

[[Imported from SVN: r6705]]

[[Imported from SVN: r6704]]

[[Imported from SVN: r6389]]

[[Imported from SVN: r5931]]

[[Imported from SVN: r4052]]

[[Imported from SVN: r4049]]

[[Imported from SVN: r4045]]

[[Imported from SVN: r4017]]

The class 'Configuration' is now called 'RigidBodyMotion', and can be parametrized by the space dimension

[[Imported from SVN: r4003]]

renaming the file 'configuration.hh' to 'rigidbodymotion.hh', which is a lot more meaningful.  Renaming the actual class will follow in a second.

[[Imported from SVN: r4002]]