Fix alt feed43 URL
url_filter: skip over all non-http(s) input
Exclude some fullrss.net garbage seen in the wild
Refactor a bit; make all as_is check for garbage
Don't emit URLs that are too long (and therefore unlikely to be real feeds); fix /wordpress/ feed URL generation
Add more wretch.cc feed URLs; don't look for blogger.com feeds
Filter out unwanted /paths on ameblo.jp
Add garbage avoidance hack