relax SVN archive

Added a system test for the reading of the Xplor pseudoatom data.

Added an Xplor NOE restraint file fragment with a methyl group.

Added support for multiple paramagnetic centre extraction to the centre() function.

Added the ave_pos flag to the pcs.centre() user function.

Some more fixes for the centre() function.

This should now be fully debugged!

The lanthanide atoms are now loaded into the relax data store for the lactose N-state model test.

Fixed a bug introduced at r9023.

The spin position was being assumed to be a list of numpy arrays, but in some cases it was simply a
numpy array.

Fixed a bug introduced at r9029.

The removal of the 'Method of Multipliers' algorithm with automatic constraint removal didn't take
the grid search into account.

Fix for the 'fixed' N-state model.

When constraints are automatically turned off for this, the minimisation algorithm should as change.

Fix for the __assemble_scaling_matrix() method for the 'fixed' N-state model.