relax SVN archive

Created the Structure.test_web_of_motion_13 system test.

This was just to be sure that the models argument was correctly handled by the structure.web_of_motion
user function.

Fixes for the Structure.test_web_of_motion_12 system test.

The PDB output was not compared to the correct results.

Implemented the models argument for the structure.web_of_motion user function.

This was previously not being used and was caught by the Structure.test_web_of_motion_12 system
test.

Created the Structure.test_web_of_motion_12 system test to show how model sets are currently ignored.

Small fixes for the Structure.test_web_of_motion_all system test.

The structure.web_of_motion user function can now handle file objects as well as file names as input.

Created the Structure.test_web_of_motion_all system test.

This is to check the new structure.web_of_motion user function.

A new PDB file with 3 models and a few atoms for testing of the structure.web_of_motion user function.

Created the structure.web_of_motion user function.

This is used to create a special PDB file which represents the atomic motions between different
structural models. Identical atoms of the selected models are concatenated into one model, within
a temporary internal structural object, and linked together using PDB CONECT records.

Fix for the assembly of atomic positions for the frame order analysis.

This is for the _minimise_setup_atomic_pos() method. Previously the warning "RelaxWarning:
Averaging the 1 atomic positions for the PCS for the spin 'x'" was being given if a single atomic
position was found.