relax SVN archive

Added a docstring to tag_setup().

Added a version 3.2 specific loop() method for the general relaxation saveframe.

Wrote the loop() method for the abstracted relaxation data bmrblib API.

This loops over and returns all relaxation data, regardless of saveframe.

Removed a useless, now abstracted loop over the relaxation data types from bmrb_read().

Fix for bmrb_read(). The object is called 'star.relaxation', not 'star.relaxation_data'.

Changes to generic_fns.relax_data.bmrb_read() for an abstracted bmrblib API.

This part of the API doesn't exist yet.

Fixes for the incorrectly named object 'star' (should have been 'self'!)

Removed the NMR-STAR version arg to the data specific bmrb_write() methods.

More fixes for the base class __init__() calling, and removed the placement of datanode into self.

Removed the initialisation of the non-existent v3.0 relaxation saveframes.