Added name and keep member variables to osg::GraphicsThread::Operation to allow

the names of the operations to be logged for stats purposes, or used when
do searches of the operation list.  The keep member variable tells the graphics
thread run loop wether to remove the entry from the list once its been called.

include/osgProducer/GraphicsContextImplementation

@@ -50,7 +50,7 @@ class OSGPRODUCER_EXPORT GraphicsContextImplementation : public osg::GraphicsCon
         /** Return true if the graphics context has been realised and is ready to use.*/
         virtual bool isRealizedImplementation() const { return _rs.valid() && _rs->isRealized(); }
 
-        /** Release the graphics context.*/
+        /** Close the graphics context.*/
         virtual void closeImplementation();
 
         /** Make this graphics context current.*/