relax SVN archive

This release corresponds to many changes to the Brownian rotational diffusion tensor.

It includes the shift to the geometric parameters

Diso = 1/3 (Dx + Dy + Dz),
Da = Dz - 1/2(Dx + Dy),
Dr = Dy - Dx / 2Da.

Numerous bugs in the old correlation time, weights, and direction cosine code have been fixed. A
few of these bugs had been fixed previously but those fixes were somehow lost. Two major problems
in the calculation of the Hessian of the ellipsoid direction cosines have been fixed and the
ellipsoid diffusion tensor now minimises orders of magnitude faster.