Set numerical fields in Cache class to zero by default

cache.h

@@ -30,8 +30,8 @@
 
 class Position {
 public:
-	float lat;
-	float lon;
+	float lat = 0;
+	float lon = 0;
 
 	Position() = default;
 	Position(float y, float x) : lat(y), lon(x) {}
@@ -43,8 +43,8 @@ public:
 	Position pos;
 	std::string name;
 	std::string size;
-	float diff;
-	float terr;
+	float diff = 0;
+	float terr = 0;
 	std::string type;
 	std::string region;
 	std::string origin;