Fix for effect Z-score direction 
Flips the interaction effect according to the mainZ. MainZ is always relative to minor allele. Flipped effect is in separate output column.
Provides goodness of fit (R-squared) in output
Merge pull request #354 from harmjanwestra/master

Fix for effect Z-score direction
Merge branch 'master' of https://github.com/molgenis/systemsgenetics