relax SVN archive

Changed the force flag of the structure.create_diff_tensor_pdb() user function to a bool.

The average CoM-pivot point vector is now labelled in PyMOL.

Changed the colour of the Average CoM-pivot point vector.

Modified the cone_pdb() function to decrease the bond widths.

Shifted structural_data from a class varible to an instance varible in the API base class.

This uses the __init__() function now.

Bug fix for the internal relax PDB data object.

The object structural_data inside the data object was a class variable, and hence each instantiation
of Internal_PDB was not resetting the object. If the object was used twice, then the data from the
first would remain.

Same bug fix as in r5412 but for tensor_pdb().

Same bug fix as in r5411 but for tensor_pdb().

Another bug fix for the cone_pdb() function.

The pymol 'load' command requires the full PDB file name.

Bug fix for the cone_pdb() function.

'pdb_file' does not exist.