added simple sentiment analysis

Added a new plot.

Merged in the AFINN sentiment dataset, merged it to the non-noise words, and then did a side-by-side barplot of the sentiments of the words used in each one of the different races scouting reports. The bars for white players are pretty even, whereas the bars for the black players greatly skew towards words with negative sentiment.

Interestingly:

> mean(black_with_sentiment$sentiment)
[1] -0.4071661
> mean(white_with_sentiment$sentiment)
[1] 0.09761388

The mean (non stop) word used to describe a black player is slightly negative, whereas the mean for white players is mostly neutral. However, when we look at the aggregate:

> sum(black_with_sentiment$sentiment)
[1] -65
> sum(white_with_sentiment$sentiment)
[1] 45

There sure is a lot more negative words for black players than there is for white players. Did I mention thanks for this data set yet?