Implemented support for float x and y mouse positions, and normalization of

mouse coords in osgGA::GUIEventAdapter, and ported osgGA camera manaipulators
to use the new normalized values.

Moved osgProducer across to tracking the window dimensions and ensure that the
internals values in osgProducer::EventAdapter are kept consistent.  Moved
the warp pointer in Viewer across to using KeyboardMouse::positionPointer().

examples/osgcameragroup/osgcameragroup.cpp

@@ -83,7 +83,7 @@ int main( int argc, char **argv )
 
     // set the keyboard mouse callback to catch the events from the windows.
     bool done = false;
-    osgProducer::KeyboardMouseCallback kbmcb(done);
+    osgProducer::KeyboardMouseCallback kbmcb(kbm,done);
     kbmcb.setStartTick(start_tick);
     
     // register the callback with the keyboard mouse manger.