function to store last_used_port
workaround for onClosed and open PORT
initial work on dynamic axis mapping

dynamic axis mapping is added to the primary CONFIG_struct and data is
being initialized/utilized only in mpu6050_10DOF_stick for now, when the
configurator side of this functionality is implemented, i will
redistribute this new code to all accel/gyro/mag libraries (lots of
copying to be done)
removing some left over variables
initializing rest of the bits to 0 (for safety)
merged m.command and m.output to a single tab
initial wrapper & files for sensor mapping
sensor mapping implementation in configurator
re-distributed axis mapping to all accelerometers
re-distributed axis mapping to all gyroscopes
re-distributed axis mapping to magnetometer
better handling of temperature readout on mpu