Use EDD_Stats for getting default earnings / sales. #1376
Ensure filtered  is included in the cache key, otherwise it will think two queries are identical, even if one has a where filter on it and the other doesn't
Tweaks to EDD_API to use EDD_Stats. #1376
Only instantiate EDD_Stats once
Add API version
Introduce edd_downloads_list_wrapper_class filter and add column count class to [downloads]. Closes #1459