[outputs] new output: RCP/Roku/SoundBridge devices

Roku SoundBridge devices can be treated as dumb speakers; they offer a
texted based protocol, RCP, that allows the server to request the Roku
device to connect to the server's stream.mp3 and provides ability to
control volume

Roku devices appear as speakers automatically via mDNS announcements on
the server _roku-rcp._tcp

owntone.conf.in

@@ -383,6 +383,23 @@ spotify {
 #	album_override = false
 }
 
+# RCP/Roku Soundbridge output settings
+# (make sure you get the capitalization of the device name right)
+#rcp "My SoundBridge device" {
+	# Enable this option to exclude a particular device from the speaker
+	# list
+#	exclude = false
+
+	# A Roku/SoundBridge can power up in 2 modes: (default) reconnect to the 
+	# previously used library (ie OwnTone) or in a 'cleared library' mode.
+	# The Roku power up behaviour is affected by how OwnTone disconnects
+	# from the Roku device.
+	#
+	# Set to false to maintain default Roku power on behaviour
+#	clear_on_close = false
+#}
+
+
 # MPD configuration (only have effect if MPD enabled - see README/INSTALL)
 mpd {
 	# TCP port to listen on for MPD client requests.