G-Tune port from Harakiri

Enabled for NAZE, ALIENWWIIF1 and ALIENWIIF3 targets
Implement G-Tune for all PID controllers
The G-Tune tuning results will be save if G-Tune mode will be disabled
during copter is disarmed.
Update PID controller and G-Tune documentation

src/main/io/rc_controls.h

@@ -48,6 +48,7 @@ typedef enum {
     BOXSERVO3,
     BOXBLACKBOX,
     BOXFAILSAFE,
+    BOXGTUNE,
     CHECKBOX_ITEM_COUNT
 } boxId_e;