Converted osgGA::GUIEventAdapter into a concrete class capable of respresenting

keyboard and mouse events.

Added osgGA::EventQueue class to support a thread safe event queue and adaption
of keyboard and mouse events.

Removed osgProducer::EventAdapter as GUIEventAdapter replaces it.

Adapted osgProducer and examples to work with the new changes to osgGA.

src/osgGA/FlightManipulator.cpp

@@ -234,7 +234,7 @@ bool FlightManipulator::calcMovement()
     if (_ga_t0.get()==NULL || _ga_t1.get()==NULL) return false;
 
 
-    double dt = _ga_t0->time()-_ga_t1->time();
+    double dt = _ga_t0->getTime()-_ga_t1->getTime();
 
     if (dt<0.0f)
     {