relax 1.2.3

Description

This is a bug fix release which corrects a segfault crash of the exponential relaxation curve-fitting modules. The bug was introduced by the shift from the makefile to Sconstruct build system. The full descriptions of all bug fixes are:

Sconstruct now does not use the '-fPIC' option during compilation which caused the exponential relaxation curve-fitting modules to segfault.

The distribution binary and source file creation Sconstruct functions now properly compress the archives.

The printout of the relax_fit.select_model function has been fixed.

The sconstruct script can now execute the fetch_docstrings code. The path previously did not include the current working directory and hence the module could not be imported.

Unselected residues are now properly ignored for the value.read function as well as all the Dasha functions.

The value.read function contained a bug where the residue number from the file was not being read. Instead the integer position within the file was being used as the residue number.

The model-free spectral density function 'calc_S2f_S2s_ts_djw_dS2s' does not exist. Therefore when using the model with the parameters {S2f, S2s, ts}, the program would throw an error and stop. The function is actually 'calc_S2f_tf_S2s_ts_djw_dS2s'. The factor 'data.s2f_s2' also had to be calculated in 'maths_fns/jw_mf_comps.py'.