ximagesrc: stops when xwindow gets closed
Fixes #656: ximagesrc: hangs when the streaming xwindow gets closed Listening for XEvent DestroyNotify to break the while loop The plugin sends FlowError and the pipeline terminates
Fixes #656: ximagesrc: hangs when the streaming xwindow gets closed Listening for XEvent DestroyNotify to break the while loop The plugin sends FlowError and the pipeline terminates