Decouple sensor alignment from all acc/gyro/mag drivers.

This resulted in the removal of duplicate logic, duplicate code and the
removal of a temporary buffer per-driver.

The NAZE specific sensor alignment is now contained within the core code
instead of in the drivers.
The sensor alignment is determines by the sensor initialisation code.
The alignment of sensor readings is now performed once and only by the
appropriate sensor code, see usages of alignSensors().

The acc/gyro/compass driver code is now more reusable since it has no
dependencies on the main code.

src/sensors_acceleration.c

@@ -8,6 +8,7 @@
 
 acc_t acc;                       // acc access functions
 uint8_t accHardware = ACC_DEFAULT;  // which accel chip is used/detected
+sensor_align_e accAlign = 0;
 
 uint16_t calibratingA = 0;      // the calibration is done is the main loop. Calibrating decreases at each cycle down to 0, then we enter in a normal mode.
 
@@ -106,6 +107,8 @@ void ACC_Common(void)
 void ACC_getADC(void)
 {
     acc.read(accADC);
+    alignSensors(accADC, accADC, accAlign);
+
     ACC_Common();
 }