Add `myip --mask/--cidr` option
Add `myip --mask/--cidr` option

Allows printing the address in CIDR notation, instead of just the IP.
E.g.:

    $ myip
    10.30.30.42

    $ myip --cidr
    10.30.30.42/16

benizi/dotfiles,benizi/dotfiles,benizi/dotfiles,benizi/dotfiles,benizi/dotfiles,benizi/dotfiles,benizi/dotfiles,benizi/dotfiles