First draft of a PMBEC class based on iskandr/mhcpred/pmbec.py
Fixing PMBEC distance so that distance(A, A) == 0
Adding positional weights
Take positional weights as an argument
Back to global max value, because local max value doesn't satisfy the triangle inequality
Merge branch 'string_distance' of https://github.com/hammerlab/immuno into string_distance