relax SVN archive

Fix for the BMRB system tests for the new interatomic data pipe object.

Spun out the automatic column width formatting code from relax_io.write_spin_data() to write_data().

The write_data() will be useful for many other columnar data printouts, and will write out to any
file handles given to it.

Initialized merge tracking via "svnmerge" with revisions "1-16842" from
svn+ssh://bugman@.../svn/relax/trunk

A large number of missing imports for the new data.interatomic module!

Created the interatomic data list and containers, and added these to the data pipe structures.

This is modelled on the molecule/residue/spin structures. The new containers have is_empty(),
from_xml() and to_xml() methods and should be fully functional with the relax infrastructure.

Created a branch to add better support for interatomic information to the relax data store.

Initialized merge tracking via "svnmerge" with revisions "1-16840" from
svn+ssh://bugman@.../svn/relax/trunk

Created a branch for implementing absolute RDCs.

relax version 2.0.0.

This is the first release of the new relax development line. For details, see
https://mail.gna.org/public/relax-devel/2012-06/msg00003.html (Message-id:
<CAED9pY-a1VBPkYisEGY8-Kb_voffP6FMY1eGVpE9RBXM0dT2rA@...>).

Updated the release checklist document for the relax 2.0 development series.