Onkyo device support

The Onkyo device support (via EISCP) is now fixed. Kudos to the miracle2k for the quick fix needed in the upstream project on https://github.com/miracle2k/onkyo-eiscp

The ago control Onkyo interface auto detects devices and supports on, off, mute, unmute, mutetoggle, vol+, vol-, setlevel (volume from 0-100) and setinput (with an input parameter). It is provided in the agocontrol-iscp package.