simplefeed 5.x-3.0

- #273934 - new option to add rel="nofollow" to source links
- more sensible options for processing # of feeds per cron run
- #272482 - fix links to feed items that have entities in them
- new option to automatically download feed items when feed is created
- #314087 - new feed stats
- #297991 - move refresh/empty links to local tasks instead of links
- #301290 - improved performance with feeds throwing errors, new option to verify feeds at input
- #307686 - fix Feedburner feeds and improve performance of feed checking
- fix feeds that are not updated on cron runs because of sharing the same $feed object
- #269029 - fix taxonomy sometimes not assigned to feed items
- #282265 - fix feeds not refreshing new content on the expected interval