New protocol for iNav flight control software

/*
 * iNav Protocol
 * Data rate is 250Kbps - lower data rate for better reliability and range
 *
 * Uses auto acknowledgment and dynamic payload size
 *     ACK payload is used for handshaking in bind phase and telemetry in data phase
 *
 * Bind payload size is 16 bytes
 * Data payload size is 8, 16 or 18 bytes dependent on variant of protocol, (small payload is read more quickly (marginal benefit))
 *
 * Bind Phase
 * uses address {0x4b,0x5c,0x6d,0x7e,0x8f}
 * uses channel 0x4c (76)
 *
 * Data Phase
 * 1) Uses the address received in bind packet
 *
 * 2) Hops between RF channels generated from the address received in bind packet.
 *    The number of RF hopping channels is set during bind handshaking:
 *        the transmitter requests a number of hopping channels in payload[7]
 *        the receiver sets ackPayload[7] with the number of hopping channels actually allocated - the transmitter must
 *        use this value.
 *    All receiver variants must support the 16 byte payload. Support for the 8 and 18 byte payload is optional.
 *
 * 3) Uses the payload size negotiated in the bind phase, payload size may be 8, 16 or 18 bytes
 * a) For 8 byte payload there are 6 channels: AETR with resolution of 1 (10-bits are used for the channel data), and AUX1
 *    and AUX2 with resolution of 4 (8-bits are used for the channel data)
 * b) For 16 byte payload there are 16 channels: eight 10-bit analog channels, two 8-bit analog channels, and six digital channels as follows:
 *    Channels 0 to 3, are the AETR channels, values 1000 to 2000 with resolution of 1 (10-bit channels)
 *    Channel AUX1 by deviation convention is used for rate, values 1000, 1500, 2000
 *    Channels AUX2 to AUX6 are binary channels, values 1000 or 2000,
 *        by deviation convention these channels are used for: flip, picture, video, headless, and return to home
 *    Channels AUX7 to AUX10 are analog channels, values 1000 to 2000 with resolution of 1 (10-bit channels)
 *    Channels AUX11 and AUX12 are analog channels, values 1000 to 2000 with resolution of 4 (8-bit channels)
 * c) For 18 byte payload there are 18 channels, the first 16 channelsar are as for 16 byte payload, and then there are two
 *    additional channels: AUX13 and AUX14 both with resolution of 4 (8-bit channels)
 */