relax SVN archive

Shifted the setting of the file and path to the specific structural object load_pdb() methods.

Modified these unit tests to check the new file and path structures.

Added some missing imports.

Switched to the internal structural object.

Updated the test_load_results() system test for the new file and path variables.

Fixed the Scientific structural object __init__().

The structural data is no longer initialised (again) and the base class __init__() method is called.

Modified the structural object code to store the file name and path.

This will cause some breakages do to the variable name changes.

Modified the test_load_results() system test to check both the file name and path.

These are not yet implemented in relax.

Changed the path to the PDB file to not be absolute.

Wrote the structural object base class method from_xml().