Control Extron scalers/switchers.

So far only tested with DSC-301-HD and IN1604 HD. It should probably also work with the DTP versions.

USAGE:
    control-dsc <SUBCOMMAND>

FLAGS:
    -h, --help       Prints help information
    -V, --version    Prints version information

SUBCOMMANDS:
    help           Prints this message or the help of the given subcommand(s)
    list           list available devices
    rescan         force rescan on server
    select         select input
    server         run as server
    stop_server    halt server