added sentiment times rate by race

Added an interesting chart (i think)

i took sentiment and then multiplied it by number of occurrences, this yielded two very different charts for white players vs black players (which you can see https://github.com/earino/Deadspin_Draftwords/blob/master/sentiment_times_rate.png)

I don't know about you, but it sure seems like a real different kind of treatment...