[rtmpdump] Escape encoding

[Steven Penny]

This site
http://kanalia.eu/player.php?id=91

provides a challenge for me. The parsed playpath end with a Carriage Return,
Line Feed. This was discussed on the forums.
http://stream-recorder.com/forum/help-getting-greek-channel-work-rtmpdump-t13743.html

A few solutions were offered up, including

- remove CRLF and prepend "mp4:" to playpath
- remove CRLF and append ".mp4" to playpath
- pass a literal Carriage return using Bash and $'\r'

KSV has noted that these solutions are nonstandard and might not be future
proof. I noticed in the MAN this paragraph

> Special characters in values may need to be escaped to prevent
> misinterpretation by the option parser. The escape encoding uses a backslash
> followed by two hexadecimal digits representing the ASCII value of the
> character. E.g., spaces must be escaped as \20 and backslashes must be escaped
> as \5c.

This looks promising, but after trying to append "\0d\0a" or just "\0d", it
appears "not to work".