extended location and latlng models

lib/model/latlng.dart

@@ -12,4 +12,18 @@ class LatLng {
   Map<String, double> toJson() {
     return {'lat': lat, 'lng': lng};
   }
+
+  @override
+  bool operator ==(Object other) {
+    if (other is! LatLng) return false;
+    return hashCode == other.hashCode;
+  }
+
+  @override
+  int get hashCode => Object.hash(lat, lng);
+
+  @override
+  String toString() {
+    return '${lat.toString()}, ${lng.toString()}';
+  }
 }