ADD: new track message, Entity class and Position class

libs/geographiclib/examples/example-Math.cpp

@@ -0,0 +1,18 @@
+// Example of using the GeographicLib::Math class
+
+#include <iostream>
+#include <exception>
+#include <GeographicLib/Math.hpp>
+
+using namespace std;
+using namespace GeographicLib;
+
+int main() {
+  try {
+    cout << Math::pi() << " " << Math::sq(Math::pi()) << "\n";
+  }
+  catch (const exception& e) {
+    cerr << "Caught exception: " << e.what() << "\n";
+    return 1;
+  }
+}