Problem imputing more than two ancestries

[mvochteloo]

A small typo seems to have introduced a bug on line 230 of the imputation Snakefile where instead of incrementing the i variable it is set to 1:
i=+1

As a result, when trying to impute more than two ancestries at the same time the third ancestry overwrites the location of the second ancestry in the ancestry_mafs.tsv file and no third row is added.

Switching the i=+1 into i+=1 should resolve this issue.