relax SVN archive

Fix for the model-free duplicate_data() method for when the data pipe is empty.

Wrote another unit test for testing the model-free duplicate_data() method.

Wrote a unit test for the model-free duplicate_data() method.

Blacklisted a few more data pipe objects in the model-free duplicate_data() method.

Prevented the sequence data to be printed out during model selection.

Added more comments related to the previous commit.

Removed the residue name from the call to generate_spin_id().

This allows point mutations in the loaded structure so that the structure doesn't exactly have to
be that for which the data was collected.

Improved the warning message.

Added a warning if the atom cannot be found in the structure.

Fix for the extraction of unit XH bond vectors.

There was a problem if the loaded sequence had residue names in mixed case when extracting atoms
from a PDB file which has all in upper case.