[[Imported from SVN: r8571]]

[[Imported from SVN: r8570]]

[[Imported from SVN: r8569]]

Because trace(sym(A)) == trace(A)

[[Imported from SVN: r8568]]

[[Imported from SVN: r8567]]

[[Imported from SVN: r8566]]

[[Imported from SVN: r8565]]

[[Imported from SVN: r8564]]

[[Imported from SVN: r8563]]

[[Imported from SVN: r8562]]

[[Imported from SVN: r8561]]

[[Imported from SVN: r8560]]

[[Imported from SVN: r8559]]

[[Imported from SVN: r8558]]

[[Imported from SVN: r8557]]

[[Imported from SVN: r8556]]

[[Imported from SVN: r8555]]

[[Imported from SVN: r8554]]

[[Imported from SVN: r8553]]

[[Imported from SVN: r8543]]

[[Imported from SVN: r8508]]

[[Imported from SVN: r8507]]

This change makes the localgeodesicfefunction test fail again.
So there must be a bug in the corresponding non-finite-difference
code.  Looking at simplex cases confirms me in this opinion.
But I don't find the bug...

[[Imported from SVN: r8463]]

[[Imported from SVN: r8462]]

[[Imported from SVN: r8460]]

[[Imported from SVN: r8409]]

implement the remaining curvature and bending terms for the energy gradient.  These are not working yet, though.

[[Imported from SVN: r8408]]

with respect to the quaternion coordinates.  Or, in other words,
the second derivative of the map from quaternions to 
orthogonal matrices.

[[Imported from SVN: r8407]]

[[Imported from SVN: r8404]]

So far, the long form of the quadratic bending energy has been
implemented and tested, and it appears to do the right thing.

This is a snapshot commit.  The code remains out-commented until
it is finished.

[[Imported from SVN: r8403]]

[[Imported from SVN: r8402]]

[[Imported from SVN: r8401]]

[[Imported from SVN: r8400]]

[[Imported from SVN: r8399]]

[[Imported from SVN: r8385]]

[[Imported from SVN: r8384]]

[[Imported from SVN: r8381]]

[[Imported from SVN: r8380]]

[[Imported from SVN: r8378]]

[[Imported from SVN: r8377]]