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.
and osgProducer to osgWrappers directory.
Enabled the build of osgWrappers/osg, osgWrappers/osgPartile and osgWrappers/osgSim,
but not osgUtil, osgDB, osgFX, osgTerrain, osgGA and osgProducer due to compile
errors. I am assuming that these compilers are fixable so I'm checked all the
source code so that members of the community can help fix them.
