On a reinit() subsystem event, reconfigure the joystick and other

inputs.  This makes it possible to hot-plug a new joystick while
FlightGear is running (as long as the user explicitly reinits the
input subsystem).

src/Input/input.cxx

@@ -179,6 +179,12 @@ FGInput::init ()
   fgRegisterMouseMotionHandler(mouseMotionHandler);
 }
 
+void
+FGInput::reinit ()
+{
+    init();
+}
+
 void 
 FGInput::update (double dt)
 {

src/Input/input.hxx

@@ -194,6 +194,7 @@ public:
   // Implementation of SGSubsystem.
   //
   virtual void init ();
+  virtual void reinit ();
   virtual void update (double dt);
   virtual void suspend ();
   virtual void resume ();