Fix penalty keyword argument in align_midi.py
Fix penalty keyword argument in align_midi.py

djitw.dtw changed the name of the penalty keyword argument to
additive_penalty in
https://github.com/craffel/djitw/commit/15b1634771bf9bfcaafca7c24ed98a25be2faa98

douglaseck/pretty-midi,craffel/pretty-midi