relax SVN archive

Changed an import order.

Different relaxation time periods for each experiment is now taken into account in the dispersion code.

Previously only the first relaxation time period was being used. This was fine for single data type
models, but was preventing the MMQ-type models from working. Now the return_r2eff_data() function
of the specific_analyses.relax_disp.disp_data module assembles and returns the relax_times data
structure which has two dimensions - the experiment type and the magnetic field strength.

Fix for the specific_analyses.relax_disp.disp_data.num_exp_types() function.

This needed updating after the change in the relaxation dispersion experiment type variables.

Change of the base relaxation dispersion experiment types.

The base CPMG-type experiment has been changed from "CPMG" to "SQ CPMG". This is for better
combined proton-heteronuclear SQ, ZQ, DQ, and MQ (MMQ) data support. The relax_disp.exp_type user
function now also as the proton SQ and MQ CPMG-types available to select from rather than the
previous behaviour of relax automatically determining the type from the spin type.

All of the CPMG experiment type variables in specific_analyses.relax_disp.variables have been
renamed for better ordering. Many changes were therefore required.

Simplified the 'MMQ 2-site' dispersion model target function.

The r2eff_mmq_2site_sq_dq_zq() and r2eff_mmq_2site_mq() functions from lib.dispersion.mmq_2site are
now aliased by the experiment_type_setup() target function method. Both functions now have matching
arguments.

The R20 values are now correctly handled in the dispersion target function for MMQ-type data.

Converted the spin specific 'r2', 'r2a', and 'r2b' dispersion parameters from lists to dictionaries.

The new parameter keys are based on the experiment type and the spectrometer frequency. These keys
are supported by the generate_r20_key() and decompose_r20_key() pair of functions in the
specific_analyses.relax_disp.disp_data module. This enables support for different R20 parameters
for each experiment type - a key piece of infrastructure for the MMQ models.

The relax_disp.select_model user function backend was modified so the parameter list only contains
one instance for each of the 'r2', 'r2a', or 'r2b' strings.

The specific_analyses.relax_disp.parameters.loop_parameters() function was modified so that the R20
key rather than frequency index is returned for the R20 parameters. Many other code changes were
required.

Missing import bug fix - this is a recent bug.

The r2eff_mmq_*() functions of lib.dispersion.mmq_2site now accept different R20A and R20B arguments.

These are set to the same thing within the dispersion target function.

Bug fixes for the previous commit (r21498).