BUG: Factor Analysis Lecture

[mmargenot]

We need to remove the calls to the internal functions in Alphalens in this lecture. The reason it was done like that in the first place was to break out the plots so that we could have exposition about each individual plot, but the scaling is very off in these plots compared to the actual tear sheets.

The fix is likely to remove all of the internal calls and aggregate all the exposition adjacent to each relevant tear sheet.