Reported by the new script 'scripts/copyright.pl'. The script has a
regex whitelist for the files that don't need copyright headers.
Removed three (mostly usesless) README files from docs/
Closes#5141
Since we're using CURLE_FTP_WEIRD_SERVER_REPLY in imap, pop3 and smtp as
more of a generic "failed to parse" introduce an alias without FTP in
the name.
Closes https://github.com/curl/curl/pull/975