relax SVN archive

The max_angle arg is now being respected. The generate_vector_dist() is complete.

Docstring fix for the generate_vector_dist() function.

Bug fix in the generate_vector_dist() function.

The centre of the distribution is called 'centre' and not 'R', as it used to be for the diffusion
tensor.

The call to generate_vector_dist() from cone_pdb() now passes in the 'CON' residue name.

A number of fixes for the new generate_vector_dist() function.

Shifted the code for generating the diffusion tensor geometric object into generate_vector_dist().

The code has been abstracted so that it can also be used to generate cone caps, or any other PDB
objects which can be generated by rotating and warping a sphere.

The inc value has already been set as a variable, so no need to replicate the number in cone_pdb().

Bug fix for the cone_pdb() function.

The rotation matrix args are 'R', not 'rotation'.

The rotation matrix is now calculated in the cone_pdb() function.

This avoids duplicated code in the generic_fns.structure module.

Modified the cone_edge() function to accept a rotation matrix as an argument.