Merge pull request #209 from Bonder-MJ/master

Addition of filtering in the input data, when using genotype harmonizer
Continue the analysis if the correlation is invalid
Merge pull request #210 from DashaZhernakova/master

Changed the code to continue the analysis if the correlation is invalid, set it to NaN
Saving truely original variance and mean
Merge pull request #211 from Bonder-MJ/master

Small optimizations in metaQTL3
Merge branch 'master' of https://github.com/molgenis/systemsgenetics