Copter: add override keyword where required

ArduCopter/mode.h

@@ -281,7 +281,7 @@ public:
     bool requires_GPS() const override { return true; }
     bool has_manual_throttle() const override { return false; }
     bool allows_arming(bool from_gcs) const override { return false; };
-    bool in_guided_mode() const { return mode() == Auto_NavGuided; }
+    bool in_guided_mode() const override { return mode() == Auto_NavGuided; }
 
     // Auto
     AutoMode mode() const { return _mode; }
@@ -303,7 +303,7 @@ public:
 
     // return true if this flight mode supports user takeoff
     //  must_nagivate is true if mode must also control horizontal position
-    virtual bool has_user_takeoff(bool must_navigate) const { return false; }
+    virtual bool has_user_takeoff(bool must_navigate) const override { return false; }
 
     void payload_place_start();
 
@@ -804,7 +804,7 @@ public:
     bool has_manual_throttle() const override { return false; }
     bool allows_arming(bool from_gcs) const override { return from_gcs; }
     bool is_autopilot() const override { return true; }
-    bool in_guided_mode() const { return true; }
+    bool in_guided_mode() const override { return true; }
     bool has_user_takeoff(bool must_navigate) const override { return true; }
 
     void set_angle(const Quaternion &q, float climb_rate_cms, bool use_yaw_rate, float yaw_rate_rads);