relax SVN archive

Added the missing molmol user function pages which should have been part of r14304.

The GUI tests are now skipped when the wx module is not present (or is broken).

This allows relax to operate without having wx installed.

Implemented all of the molmol user function pages and menu entries.

These include:
molmol.clear_history
molmol.command
molmol.macro_exec
molmol.ribbon
molmol.tensor_pdb
molmol.view
molmol.write

Some docstring improvements to a few of the molmol user functions.

Added some Molmol graphics.

Converted the molmol and pymol user function docstrings to the new design.

Alphabetical ordering of the structure user function menu entries.

All of the boolean_selector SetValue() calls have been changed to the 'default' arg.

This will allow the boolean_selector object to be changed into anything, and all user functions
should still be 100% functional.

Implemented the structure.get_pos user function page and menu entry.

Implemented two more of the structure user function pages and menu entries.

These are:
structure.create_vector_dist
structure.create_diff_tensor_pdb

The wizard graphics are taken from my paper:

d'Auvergne, E. J. and Gooley, P. R. (2008). Optimisation of NMR dynamic models II. A new methodology
for the dual optimisation of the model-free parameters and the Brownian rotational diffusion tensor.
J. Biomol. NMR, 40(2), 121-133. (http://dx.doi.org/10.1007/s10858-007-9213-3).