Improved UART Timeout

Major:
- Improved UART Timeout: Apparently, the UART data Rx/Tx is quite unreliable (especially under motor load) leading to very often out-of-sync issues. This change allows to reset the DMA more often, leading to a faster re-sync of the UART transmission and thus avoiding UART timeout. Issue #1

Minor:
- added #define MPU_SENSOR_ENABLE to allow to enable/disable the MPU6050 sensor and save code size if the sensors is not needed
- fixed the orientation in the Processing sketch
- updated ReadMe

Inc/mpu6050_dmp.h

@@ -23,6 +23,7 @@
 // Define to prevent recursive inclusion
 #ifndef MPU6050_DMP_H
 #define MPU6050_DMP_H
+#ifdef  MPU_SENSOR_ENABLE
 
 #include <stdint.h>
 
@@ -103,5 +104,6 @@ int dmp_read_fifo(short *gyro, short *accel, long *quat,
     unsigned long *timestamp, short *sensors, unsigned char *more);
 
 
-#endif
+#endif // MPU_SENSOR_ENABLE
+#endif // MPU6050_DMP_H