[FEATURE,TEST]: CiRT features and tests added to MRMRTNormalizer

As discussed, here are a few proposed changes to the MRMRTNormalizer class.

The most important are the following:
- tests for RANSAC / independence of GSL code
- rm_outliers_ransac is a wrapper function that converts the rm_outliers_iterative parameters to the units that RANSAC requires. The parameter max_rt_threshold is the most critical and is estimated based on the gradient (see comments below)
- residual outlier candidate selection instead of Jackknife approach is selected by default (analogously to the implementation in SpectraST)