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.

src/osg/GraphicsThread.cpp

@@ -21,7 +21,11 @@ using namespace OpenThreads;
 
 struct BlockOperation : public GraphicsThread::Operation, public Block
 {
-    BlockOperation() { reset(); }
+    BlockOperation():
+        GraphicsThread::Operation("Block",false)
+    {
+        reset();
+    }
 
     virtual void operator () (GraphicsContext*)
     {