ArduCopter: add tuning of throttle rate controller's I term (THROTTLE_KI)

ArduCopter/ArduCopter.pde

@@ -2063,6 +2063,10 @@ static void tuning(){
         g.pid_throttle.kP(tuning_value);
         break;
 
+    case CH6_THROTTLE_KI:
+        g.pid_throttle.kI(tuning_value);
+        break;
+
     case CH6_TOP_BOTTOM_RATIO:
         motors.top_bottom_ratio = tuning_value;
         break;

ArduCopter/defines.h

@@ -169,9 +169,10 @@
 #define CH6_YAW_RATE_KD 26
 // Throttle
 #define CH6_THROTTLE_KP 7
-#define CH6_THR_ACCEL_KP 33
-#define CH6_THR_ACCEL_KI 34
-#define CH6_THR_ACCEL_KD 35
+#define CH6_THROTTLE_KI 33
+#define CH6_THR_ACCEL_KP 34
+#define CH6_THR_ACCEL_KI 35
+#define CH6_THR_ACCEL_KD 36
 // Extras
 #define CH6_TOP_BOTTOM_RATIO 8
 #define CH6_RELAY 9