Changed Contents to API Reference
Disabled using --different and --encrypt together
Made -H a synonym for -h and -h show help on error

The previous -hheader:value still works fine, I just added
-Hheader:value since so many folks used to curl do that. And folks
are also typing things like "swiftly get -h" to try to get help and
instead were just getting an annoying "-h option requires an
argument", so I made that case also output the command help.