relax SVN archive

Renamed all instances of RelaxRunError with RelaxPipeError, and modified the error message.

Renamed all instances of RelaxNoRunError to RelaxNoPipeError, and updated the error message.

Added two unit tests for the generic_fns.selection.return_single_residue_info() function.

Added two unit tests for the generic_fns.selection.return_molecule() function.

Also made the function fail properly when no data pipe exists.

Added another unit test for the generic_fns.selection.return_residue() function.

Added a test for the failure of the generic_fns.selection.return_residue() function.

This tests the failure of asking for a non-existent data pipe and the function has been fixed to
fail appropriately.

A large number of changes to make the residue.copy() user function fully functional.

Now residue data can be copied within a single molecule, between molecules, and between data pipes.

More unit tests for the generic_fns.residue.copy() function.

The current test was renamed. Two new tests were added for copying between molecules and copying
between data pipes.

Spelling correction.

Alphabetical arrangement of the residue user functions.