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
- CURLOPT_HEADERFUNCTION: add newlines
- CURLOPT_INTERLEAVEFUNCTION: fix the description of 'userdata'
- CURLOPT_READDATA: mention crashes, same as in CURLOPT_WRITEDATA
- CURLOPT_READFUNCTION: rename 'instream' to 'userdata' and explain
how to set it
Closes https://github.com/curl/curl/pull/2868