Use a MAX_DISTANCE instead of -1

components/ratgdo/sensor/ratgdo_sensor.cpp

@@ -7,6 +7,7 @@ namespace ratgdo {
 
     static const char* const TAG = "ratgdo.sensor";
     static const int MIN_DISTANCE = 100; // ignore bugs crawling on the distance sensor & dust protection film
+    static const int MAX_DISTANCE = 4500; // default maximum distance
 
     void RATGDOSensor::setup()
     {
@@ -96,6 +97,8 @@ namespace ratgdo {
                     }
                 }
 
+                if(maxDistance < 0) maxDistance = MAX_DISTANCE;
+
                 //maxDistance = objCount == 0 ? -1 : pDistanceData->RangeData[objCount - 1].RangeMilliMeter;
                 /* 
                  * if the sensor is pointed at glass, there are many error -1 readings which will fill the