Extended manpage-syntax.pl (run by test 1173) to check that every man
page for a libcurl option has an EXAMPLE section that is more than two
lines. Then fixed all errors it found and added examples.
Reviewed-by: Daniel Gustafsson
Closes#7656
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