Initial implementation of Runaway Takeoff Prevention (anti-taz)

Detects runaway pidSum values on takeoff and auto-disarms to prevent the "Tasmanian Devil" caused by incorrect props, wrong motor order/direction, incorrect flight controller orientation, etc.  After a successful takeoff and normal flight is detected the feature is disabled for the remainder of the battery.

src/main/fc/rc_controls.c

@@ -195,6 +195,14 @@ void processRcStickPositions(throttleStatus_e throttleStatus)
             else {
                 beeper(BEEPER_DISARM_REPEAT);     // sound tone while stick held
                 repeatAfter(STICK_AUTOREPEAT_MS); // disarm tone will repeat
+
+#ifdef USE_RUNAWAY_TAKEOFF
+                // Unset the ARMING_DISABLED_RUNAWAY_TAKEOFF arming disabled flag that might have been set
+                // by a runaway pidSum detection auto-disarm.
+                // This forces the pilot to explicitly perform a disarm sequence (even though we're implicitly disarmed)
+                // before they're able to rearm
+                unsetArmingDisabled(ARMING_DISABLED_RUNAWAY_TAKEOFF);
+#endif
             }
         }
         return;