Add Average DL Download

[daryllabar]

Not sure how hard this would be, but sometimes it's hard to compare tools using just the downloads for this version, vs total. If one tool creates lots and lots of new versions, it would result it getting downloaded much more often, making it look like it's overly popular for the total download count.

Request: Have a daily download count for the latest version, or for all time, or both (haven't thought this through). Since you know the date it was first published and the total number of downloads, the math should be easy. This would be a better source for ranking popularity among tools.