Speed up accelerometer data intake.

The LIS2DH12 driver performed an unnecessary endianness conversion, as
data from the sensor was already coming in little-endian format.  The
MMA8652FC driver is now using the rev16 opcode to perform the swap
rather than doing all the bitshuffling operations in multiple steps.

workspace/TS100/Core/Inc/MMA8652FC.hpp

@@ -19,7 +19,7 @@ public:
 
 	static void initalize();		// Initalize the system
 	static Orientation getOrientation();// Reads the I2C register and returns the orientation (true == left)
-	static void getAxisReadings(int16_t *x, int16_t *y, int16_t *z);
+	static void getAxisReadings(int16_t& x, int16_t& y, int16_t& z);
 
 private:
 };