relax SVN archive

Modified the internal structural object backend for the structure.read_pdb user function.

The MolContainer._det_pdb_element() method for handling PDB files with missing element information
has been updated to use the Periodic_table.has_element() method to check if the PDB atom name
corresponds to any atoms in the periodic table. This allows for far greater support for HETATOMS
and all of the metals.

Added 4 unit tests to the _lib.test_periodic_table module for the Periodic_table.has_element() method.

Created the Periodic_table.has_element() method for the lib.periodic_table module.

This is used to simply check if a given symbol exists as an atom in the periodic table.

Bug fix for the structure.align user function for when no data pipes are supplied.

The compression level for results files can now be set in the frame order auto-analysis.

This is via the new argument results_compress_type, which is used to set the compress_type argument
of the results.write user function. The results reading parts of the auto-analysis have been
updated to allow uncompressed, bzip2 compressed, and gzip compressed files to be handled.

The intermediate results are no longer stored in the Frame_order.test_auto_analysis system test.

This drops the test timing on one system from ~190 seconds to ~50 seconds.

The intermediate results storing can now be turned off in the frame order auto-analysis.

The new store_intermediate Boolean argument has been added to the analysis to allow the storage of
these results to be turned on or off.

The grid search can now be skipped for the rigid model in the frame order auto-analysis.

If the input 3D structures are close to the real solution, the grid search over the translational
and rotation parameters of the rigid model could be skipped. This speeds up the analysis and can
help find the real solution in problematic cases.

Created the Optimisation.has_grid() method for the frame order auto-analysis.

This is used to test if the optimisation settings object has a grid search defined.

Speed up of the Frame_order.test_auto_analysis system test.

The splitting of the rigid model grid search into rotation and translation parts has been
reactivated.