Minor fixes and changes

flix/control.ino

@@ -169,6 +169,7 @@ const char* getModeName() {
 		case MANUAL: return "MANUAL";
 		case ACRO: return "ACRO";
 		case STAB: return "STAB";
+		case USER: return "USER";
 		default: return "UNKNOWN";
 	}
 }

flix/quaternion.h

@@ -167,6 +167,7 @@ public:
 		return Vector(res.x, res.y, res.z);
 	}
 
+	// Rotate vector by quaternion
 	inline Vector rotate(const Vector& v) {
 		return conjugateInversed(v);
 	}