Add set support to mixpanel.
Add set support to mixpanel.

telmofcosta/analytical,Bargains4Business/analytical,backupify/analytical,jkrall/analytical,Bargains4Business/analytical,Bargains4Business/analytical,backupify/analytical,jkrall/analytical,pedrocarrico/analytical,telmofcosta/analytical,Seedrs/analytical,Bargains4Business/analytical,Seedrs/analytical