relax SVN archive

Shifted the grid search limits, diagonal scaling, and grid size test into new separate methods.

Whoops, removal of the old code which was shifted into a new function in r5170.

The diffusion tensor grid search configuration has been shifted into its own function.

Started the break up of the insanely complex model-free minimisation methods in specific_fns.

The configuration of the spin specific part of the grid search has been shifted into its own
function.

Better epydoc support for the equations and title of the unit_axes() function.

Better epydoc support for the equations of the fold_angles() function.

Replaced all '@return type:' with '@rtype:'.

Better epydoc support for the equations of the svd() function.

Fix for the map_labels() docstring.

Better epydoc support for the equations of the kappa() function.