Fix OSCPA/Store-Pathfix#350 by merging @cj52973's code with @joelmusheno's, basically just adding filtering on product being on sale, in the future, planned, and a conference. (There were some bugs in Chris' version that resulted in nothing being returned.) Tested with my account and Chris' and the data looks legit. The changes are also simple enough that I'm pretty confident this is fine and good.