Relocate mcjoin and fix missing -r in getopt()

Signed-off-by: Joachim Nilsson <troglobit@gmail.com>
mping: Useful multicast ping tool (sender/receiver)

Signed-off-by: Joachim Nilsson <troglobit@gmail.com>
Convert string encoded hex to readable text: 66:6f:6f --> foo

Signed-off-by: Joachim Nilsson <troglobit@gmail.com>