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
Adds access to the effectively used protocol/scheme to both libcurl and
curl, both in string and numeric (CURLPROTO_*) form.
Note that the string form will be uppercase, as it is just the internal
string.
As these strings are declared internally as const, and all other strings
returned by curl_easy_getinfo() are de-facto const as well, string
handling in getinfo.c got const-ified.
Closes#1137