[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.h

@@ -0,0 +1,49 @@
+/* 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.
+ */
+
+//! \file
+
+#ifndef BLACKSIM_XSWIFTBUS_NAVDATAREFERENCE_H
+#define BLACKSIM_XSWIFTBUS_NAVDATAREFERENCE_H
+
+namespace XSwiftBus
+{
+    //! Simplified version of CNavDataReference of \sa BlackMisc::Simulation::XPlane::CNavDataReference
+    class CNavDataReference
+    {
+    public:
+        //! Default constructor
+        CNavDataReference() = default;
+
+        //! Constructor
+        CNavDataReference(int id, double latitudeDegrees, double longitudeDegrees)
+            : m_id(id), m_latitudeDegrees(latitudeDegrees), m_longitudeDegrees(longitudeDegrees)
+        { }
+
+        //! \copydoc BlackMisc::Simulation::XPlane::CNavDataReference::id
+        int id() const { return m_id; }
+
+        //! \copydoc BlackMisc::Simulation::XPlane::CNavDataReference::latitude
+        double latitude() const { return m_latitudeDegrees; }
+
+        //! \copydoc BlackMisc::Simulation::XPlane::CNavDataReference::longitude
+        double longitude() const { return m_longitudeDegrees; }
+
+    private:
+        int m_id = 0;
+        double m_latitudeDegrees = 0.0;
+        double m_longitudeDegrees = 0.0;
+    };
+
+    //! Free function to calculate great circle distance
+    double calculateGreatCircleDistance(const CNavDataReference &a, const CNavDataReference &b);
+
+} // ns
+
+#endif // guard