relax SVN archive

Fix for bug #10323 (https://gna.org/bugs/?10323).

This bug was reported by Douglas Kojetin <douglas dot kojetin at gmail dot com>.

The fix was to simply use the same fix which went into the equivalent model-free code years and
years ago!

Small comment fix.

Lots of simplifications to the generic_fns.spin.copy() function.

The generic_fns.residue.create() function now allows residues to be added to different molecules.

One of the comments was incorrect.

Small simplification to the generic_fns.spin.create() function.

Completed the generic_fns.residue.create() docstring.

Completed the generic_fns.spin.create() docstring.

Simplification of the loops in the generic_fns.residue.renumber() function.

Simplified the loop of the generic_fns.residue.rename() function.