Merge branch 'NIFTy_4' into yango_minimizer

This merge is done in order to make the yango minimizer and the krylov sampling available in the same branch while still keeping the yango minimizer out of the master branch for NIFTy
2 jobs for yango_minimizer in 1 minute and 39 seconds (queued for 1 second)
Status Job ID Name Coverage
  Test
passed #537852
test_python2_scalar

00:01:39

67.0%
passed #537853
test_python3_scalar

00:01:09