Generalize Average Feature

The two commits in wsuv-deployed-fall-20200902 add a new feature; it'd be great if you guys could take ownership of this; review it; talk to Ben about it's functionality (he uses it); and eventually see if CMU is interested.

Updates 3/27: Submitted questionnaire to CMU's team on accepting feature.

Updates 3/29: Submitted PR to Autolab

Updates 4/6: Talking with CMU on differences between our PR and their existing code

Currently waiting for further feedback on the PR, unlikely to get more info back before the end of this school year.