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
This makes it easier for emacs users to automatically get the right
2-space indentation when they edit curl source files.
c++-mode is in there as well because Emacs can't easily know if
something is a C or C++ header.
Closes#574