Robo-Sentry Communications Protocols.

Serial Messages between the Edison and the Arduino Robot controller.
Messages start with a #, then an ID character, then the data as defined below.
Since we will only be transfering basic numberic values, those will be encoded as HEX.
Character position will be used for decoding rather then having delimiters.
All messages are terminated with a <cr><lf>

ASCII ID Byte   Message Description
0               undefined/reserved/not set
M               Mode
D               Drive
P               Position
G               Goto
R               RFID
O               Obstuct

Mode message
 The mode command places the bot in either manual mode or auto mode. Based on this mode, many of the messages change
 control direction. For example, when in Manual mode, the Drive message controls the motor drive directly. In Auto mode
 The Drive message is an output from the bot for motor status.

    MA<cr><lf>
    A is operation mode, A = Auto, M = Manual

Drive message
    Basic motor control (Manual) or status (Auto)
    DALLBRR<cr><lf>
        D is message ID
        A is Left motor direction F for forward, R for reverse
        LL for left motor PWM value 00-FF with 00 meaning 0%
        B is Right motor direction
        RR is right motor PWM 00-FF

    Example
        DF47F64<cr><lf>  is Drive Left motor forward at 0x47H, Right motor forward at 0x64

Position message
    Position data the bot maintains via it's motor encoders. This message is sent by the bot at regular intervals to
    update it's status. If received this message is taken as a calibration setting the X,Y bot position to the given cords.

    PXXXXXXXYYYYYYY<cr><lf>
        P is message ID
        XXXXXXXX  X position count, 64 Bits, Signed Long
        YYYYYYYY  Y position count, 64 Bits, Signed Long

    Example
        P0123456701234567<cr><lf>
        01234567 Counts of X
        02345667 Counts of Y

Goto message
    This message commands the bot in Automatic mode to find it's way to the specified X,Y position. The encoding
    matches the Position message above

    GXXXXXXXYYYYYYY<cr><lf>
        G is message ID
        XXXXXXXX  X position count, 64 Bits, Signed Long
        YYYYYYYY  Y position count, 64 Bits, Signed Long

    Example
        G0123456701234567<cr><lf>
        Goto 01234567 Counts of X
        and  02345667 Counts of Y

RFID message
    This message is output by the bot when it reads a valid ID via it's RFID reader.
    R?<cr><lf>
        R is the ID
        ? Is the data, don't know how much to expect, its the unique ID part of what's read.

Obstuct message
    Output by the bot at a regular interval with status of the obstruction detectors.  For now I'm assuming there
    can be a numberic output for range which can be mapped into a signed 16 bit int.

    OAAAABBBBCCCCDDDD<cr><lf>
        O       Message ID
        AAAA    Value for Left front sensor
        BBBB    Right front
        CCCC    Left rear
        DDDD    Right rear