asyncify

This was in the raw-polls.csv files, e.g.: https://github.com/fivethirtyeight/data/blob/master/pollster-ratings/2017/raw-polls.csv https://github.com/fivethirtyeight/data/blob/master/pollster-ratings/2018/raw-polls.csv https://github.com/fivethirtyeight/data/blob/master/pollster-ratings/2019/raw-polls.csv Found 3 minor data flaws that I think affect derived result and rating for Trafalgar Group. I concatenated into one...