relax SVN archive

Converted a few of the N-state model system tests to use the new rdc.read definition.

Added the script for the system test of the last commit (r16856).

Created an initial system (and GUI) test for the absolute RDC concept.

Converted some of the test suite RDC data to use the double spin ID format for interatomic data.

Converted the only sample script which uses the rdc.read user function to the changed definition.

Converted the rdc.read user function backend to the new interatomic data design.

Converted the stereochemistry auto-analysis to use the new rdc.read definition.

Added the 'absolute' keyword arg to the rdc.read user function definition.

This will be used to mark RDCs as being unsigned.

Merged revisions 16847 via svnmerge from
svn+ssh://bugman@.../svn/relax/trunk

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r16847 | bugman | 2012-06-11 19:55:17 +0200 (Mon, 11 Jun 2012) | 6 lines

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.
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Converted the rdc.read user function definition to use the interatomic data objects.

This is currently only for the front ends of the user function.