Removed redundent TerrainGeometry classes, and adding double buffer of

internal data within GeometryTechinque in prep for support multi-threaded
set up and rendering of terrain.

src/osgWrappers/osg/OperationThread.cpp

@@ -236,5 +236,7 @@ BEGIN_OBJECT_REFLECTOR(osg::RefBlock)
 	               "");
 END_REFLECTOR
 
+TYPE_NAME_ALIAS(osg::OperationThread, osg::OperationsThread)
+
 STD_SET_REFLECTOR(std::set< osg::OperationThread * >)