evaluate_residuals now returns just residuals and corresponds
to pure unweighted chi_2. It is still necessary for
Fumili algorithm and for compatibility with lmfit, but
should be replaced by scalar objective value otherwise.

Redmine: #2316

1. self consistence for q-defined reflectometry with resolution
2. python export for reflectometry with resolutions
3. standard test for q-defined reflectometry with relative resolution

Reference file is an exact copy of BeamFullDivergence.int.gz

Reference file is an exact copy of BeamAngularDivergence.int.gz

The results of the two tests (SpecularDivergentBeam and SpecularDivergentBeamCopy)
was compared with self-consistent test locally

Switch to absolute value of difference in GISAS plot observer for better comparison with original images

Redmine: #2259

Redmine: #2259

Redmine: #2259

Redmine: #2259