Don't truncate Location::distance results to meters

When doing computations on detailed navigation paths the errors introduced
by this actually accumulate to relevant sizes.

autotests/data/hafas/canceled-journey-with-path.out.json

@@ -3,7 +3,7 @@
         "sections": [
             {
                 "disruptionEffect": "NoService",
-                "distance": 163558,
+                "distance": 163559,
                 "from": {
                     "identifier": {
                         "unit-test": "8011113"

src/lib/backends/ivvassparser.cpp

@@ -274,7 +274,7 @@ static Path parseDirections(Path &&fullPath, const QJsonArray &directions)
 
         int nextSecStart = prevSecStart;
         for (; nextSecStart < poly.size(); ++nextSecStart) {
-            if (Location::distance(lat, lon, poly[nextSecStart].y(), poly[nextSecStart].x()) == 0) {
+            if (Location::distance(lat, lon, poly[nextSecStart].y(), poly[nextSecStart].x()) < 1.0f) {
                 break;
             }
         }

src/lib/datatypes/location.cpp

@@ -421,7 +421,7 @@ Location Location::merge(const Location &lhs, const Location &rhs)
 }
 
 // see https://en.wikipedia.org/wiki/Haversine_formula
-int Location::distance(float lat1, float lon1, float lat2, float lon2)
+float Location::distance(float lat1, float lon1, float lat2, float lon2)
 {
     const auto degToRad = M_PI / 180.0;
     const auto earthRadius = 6371000.0; // in meters
@@ -433,10 +433,10 @@ int Location::distance(float lat1, float lon1, float lat2, float lon2)
     return 2.0 * earthRadius * atan2(sqrt(a), sqrt(1.0 - a));
 }
 
-int Location::distance(const Location &lhs, const Location &rhs)
+float Location::distance(const Location &lhs, const Location &rhs)
 {
     if (!lhs.hasCoordinate() || !rhs.hasCoordinate()) {
-        return std::numeric_limits<int>::max();
+        return std::numeric_limits<float>::max();
     }
     return Location::distance(lhs.latitude(), lhs.longitude(), rhs.latitude(), rhs.longitude());
 }

src/lib/datatypes/location.h

@@ -105,11 +105,11 @@ public:
     static Location merge(const Location &lhs, const Location &rhs);
 
     /** Compute the distance between two geo coordinates, in meters. */
-    static int distance(float lat1, float lon1, float lat2, float lon2);
+    static float distance(float lat1, float lon1, float lat2, float lon2);
     /** Computes the distance in meters between two locations.
      *  Returns MAX_INT if one of the arguments has no coordinates set.
      */
-    static int distance(const Location &lhs, const Location &rhs);
+    static float distance(const Location &lhs, const Location &rhs);
 
     RentalVehicleStation rentalVehicleStation() const;
     [[deprecated("use setData instead")]] void setRentalVehicleStation(const RentalVehicleStation &dock);