Feature request: by-group analysis (A / B testing)

RickPack

DELETE ME

RickPack

Split out filtervar parameter in fbadGstats function into new function for (informal?): 1. A/B testing 2. by-group comparisons, at least for "Amount Spent" [Might an ad have performed worse than another because the FB algorithm happened to invest more in a particular low-performing age group (25-34)]?