relax SVN archive

Bug fix for create_cone_pdb() for when a rotation matrix is supplied.

The cone central axis was not being rotated!

Bug fix for cone_edge() for when a rotation matrix is supplied.

The latitude points were not being rotated.

Fix for create_cone_pdb() for when a rotation matrix is supplied.

Created the new fn create_cone_pdb() which can be used to create PDB file representations of cones.

cone_pdb() now takes the new EDG residue for the cone edge into account.

Rewrote the stitch_cone_to_edge() function to handle the arbitrarily shaped cones.

Modified the cone_edge() function to add atoms for the latitude lines as well.

Added theta_max() methods to all the isotropic cone classes.

This is for determining theta from the phi polar angle.

Added the cones module to the __all__ package list.

The back-calculation of Ri data via model-free and diffusion tensors has been added to the system tests.