Mathias Fröhlich:

This patch makes use of the vectors now available in simgear with that past
patch. And using that it simplyfies the carrier code somehow.

- Small additional factory's to the quaternion code are done in the simgear
  part. Also more explicit unit names in the factory functions.
- The flightgear part makes use of them and simplyfies some computations
  especially in the carrier code.
- The data part fixes the coordinate frames I used for the park positions in
  the carrier to match the usual ones. I believed that I had done so, but it
  was definitly different. Also there are more parking positions avaliable now.

simgear/math/SGVec3.hxx

@@ -42,6 +42,13 @@ public:
   T& operator()(unsigned i)
   { return _data[i]; }
 
+  /// Access raw data by index, the index is unchecked
+  const T& operator[](unsigned i) const
+  { return _data[i]; }
+  /// Access raw data by index, the index is unchecked
+  T& operator[](unsigned i)
+  { return _data[i]; }
+
   /// Access the x component
   const T& x(void) const
   { return _data[0]; }