Added Camera::s/getAllowsEventFocus() method to allow osgViewer to have non interfactive cameras such as RTT ones

include/osg/Camera

@@ -64,6 +64,13 @@ class OSG_EXPORT Camera : public Transform, public CullSettings
         const osg::Stats* getStats() const { return _stats.get(); }
 
 
+        /** Set whether this camera allows events to be generated by the associated graphics window to be associated with this camera.*/
+        void setAllowEventFocus(bool focus) { _allowEventFocus = focus; }
+
+        /** Get whether this camera allows events to be generated by the associated graphics window to be associated with this camera.*/
+        bool getAllowEventFocus() const { return _allowEventFocus; }
+
+
         /** Sets the clear color. */
         inline void setClearColor(const Vec4& color) { _clearColor = color; }
 
@@ -401,6 +408,8 @@ class OSG_EXPORT Camera : public Transform, public CullSettings
         View*                       _view;
 
         osg::ref_ptr<osg::Stats>    _stats;
+
+        bool                        _allowEventFocus;
         
         Vec4                        _clearColor;
         GLbitfield                  _clearMask;