[xswiftbus] Remove BlackMisc dependency

There were only very few classes used from Blackmisc after the interpolator
was moved to the driver. Therefore replace those few classes with
a simple alternative and remove BlackMisc from xswiftbus.

src/xswiftbus/navdatareference.cpp

@@ -0,0 +1,39 @@
+/* Copyright (C) 2018
+ * swift Project Community / Contributors
+ *
+ * This file is part of swift project. It is subject to the license terms in the LICENSE file found in the top-level
+ * directory of this distribution and at http://www.swift-project.org/license.html. No part of swift project,
+ * including this file, may be copied, modified, propagated, or distributed except according to the terms
+ * contained in the LICENSE file.
+ */
+
+#include "navdatareference.h"
+#include <cmath>
+
+namespace XSwiftBus
+{
+
+    //! Converts degree to radian
+    inline double degreeToRadian(double angle)
+    {
+        return M_PI * angle / 180.0;
+    }
+
+    //! Returns the great circle distance between to nav data references
+    double calculateGreatCircleDistance(const CNavDataReference &a, const CNavDataReference &b)
+    {
+        const static double c_earthRadiusKm = 6372.8;
+
+        double latRad1 = degreeToRadian(a.latitude());
+        double latRad2 = degreeToRadian(b.latitude());
+        double lonRad1 = degreeToRadian(a.longitude());
+        double lonRad2 = degreeToRadian(b.longitude());
+
+        double diffLa = latRad2 - latRad1;
+        double doffLo = lonRad2 - lonRad1;
+
+        double computation = asin(sqrt(sin(diffLa / 2) * sin(diffLa / 2) + cos(latRad1) * cos(latRad2) * sin(doffLo / 2) * sin(doffLo / 2)));
+        return 2 * c_earthRadiusKm * computation;
+    }
+
+}