relax SVN archive

Bug fix: Added the function __deselect_spins() to remove spins with too little data.

This fixes bug #14428 (http://gna.org/bugs/?14428) reported by Pierre-Yves Savard <pierre-yves dott
savard at bcm dot ulaval dot ca>.

The new function is almost identical to that used in the model-free analysis performed by relax in
that spins with no or too little data, or those which would be over-fit are removed from the
analysis.

Modified the grid search calls due to changes in minfx.

Redesigned the model-free grid search setup around the new minfx interface.

Removed some trailing whitespace.

Another clean out of the grid search setup.

Added a comment line.

Redesigned the N-state model grid search setup around the new minfx interface.

A bit of a clean up of the relaxation curve fitting minimise() method.

Redesigned the relaxation curve fitting grid search for the new design of the minfx grid search.

Added a series of checks to the test_curve_fitting() system test.