Suspicious k in FAD

[murrellb]

I suspect that k=5 is meant to be k=6 here:

dists = [corrected_kmer_dist_full(k[3],s[3],k=5) for k in current_set]

This should only change the scaling, so the minimum (which is what is used here) should be preserved, but it is an odd choice. Please change to 6, and confirm behavior doesn't change.