relax SVN archive

Manually ported the 1.2.14 tag CHANGES file changes to the 1.2 line.

The command used was:
svn merge -r7122:7123 svn+ssh://bugman@.../svn/relax/tags/1.2.14 .

relax version 1.2.15.

This is a minor bug fix release.

Reverted r8029. This 'svn cp' went to the wrong place!

The command used on a checked out copy of the 1.2.14 tag was:
svn merge -r8029:8028 .

relax version 1.2.15.

This is a minor bug fix release.

Fix for the __atom_index() method. This is a partial fix for bug #12637 (https://gna.org/bugs/?12637).

The struct_index of None is now handled.

Added a lactose PDB file and 2 system tests reading this file.

Wrote 8 system tests for reading various PDB files using the internal and Scientific python objects.

Wrote the interface for the spectrum.replicated() user function.

Slight modification to the missing data RelaxWarning message.

Added a catch for missing data in the grace.write() user function back end.

A RelaxWarning is now thrown saying that an empty file will be created.