Add RFCOMM service routine, to send pending configuration requests on RFCOMM channels. Add in RFCOMM channel config flags, to determine which configuration commands have been sent and received.

Add a new RFCOMM_SendChannelSignals() function to transmit a change in V24 terminal handshake lines to the receiving device.

Prevent SABM packets sent to the control DLCI in the RFCOMM layer from creating a new channel entry, as the control DLCI does not have connection data associated with it.

Fix up MSC control packet handling so that received responses can be acknowledged correctly, so that the RFCOMM layer can record when the receiving device has ACKed a sent change in V24 terminal handshake lines.