[COMPAS Example] Switched variable names

[LiFaytheGoblin]

https://github.com/dssg/aequitas/blob/master/docs/source/examples/compas_demo.ipynb

Under "Levels of recidivism" you write label_by_age = sns.countplot(x="sex", hue="label_value", data=df, palette=aq_palette) and then label_by_sex = sns.countplot(x="age_cat", hue="label_value", data=df, palette=aq_palette). It seems like the names were switched.

Also I can make a pull request for the issues I am filing.