added part about FITC large scale regression since roman fixed the bugs recently
initial draft for (x-) evaluation, and model selection notebook
test cross validation fold indices
modified one file to include all tests
remove file
fixed typos in crossvalidation tests
Merge pull request #1796 from karlnapf/develop

added FITC part of GP notebook and X-validation notebook draft
test covering of all indices
test covering of all indices
added check for disjoint folds
Merge pull request #1795 from Saurabh7/foldindices

Foldindices