Dtw

The functionality works, but we are getting +1 too many correct examples for accuracy. I don't know why.

If we set count = -1, it will hackishly fix this problem. I made a Piazza post so hopefully we hear back. Otherwise, I made the pull request because everything seems to be working and you can do your part tomorrow.
distances = [ (train_key, self._dtw(test_vector, train_vector) for train_key, train_vector in self.train_set.iteritems() ]