duplicate-check problem on the mapping file (-m) #100
Description
I think right now if people provide only column 1 and column 3 (so col 3 would be appended to col 1), GToTree says there are duplicate labels and stops. It should have that check for col 2, since that's complete replacement of the label. But when there is a col 3, that needs to be appended to col 1 (or col 2 if that's included also) before checking if they are all unique.