Added ImageStream::quit(bool) for exiting from video threads, and added

clean up to OsgCameGroup to quit movie threads automatically.

include/osg/ImageStream

@@ -50,6 +50,8 @@ class SG_EXPORT ImageStream : public Image
         virtual void pause() { _status=PAUSED; }
 
         virtual void rewind() { _status=REWINDING; }
+        
+        virtual void quit(bool /*wiatForThreadToExit*/ = true) {}
 
         StreamStatus getStatus() { return _status; }
         

include/osgProducer/OsgCameraGroup

@@ -42,7 +42,7 @@ class OSGPRODUCER_EXPORT OsgCameraGroup : public Producer::CameraGroup
 
         OsgCameraGroup(osg::ArgumentParser& arguments);
 
-        virtual ~OsgCameraGroup() {}
+        virtual ~OsgCameraGroup();
 
 
         void setApplicationUsage(osg::ApplicationUsage* au) { _applicationUsage = au; }