[PD] gop drawing

Hi list, I'm implementing graph-on-parent drawing in my port of the Pd-l2ork GUI to HTML5.

What I've come across is that both glist_delete and graph_vis will send a message to the GUI to erase the objects shown in the GOP window. So when you select a gop subpatch and click <BackSpace>, Pd sends two "delete" messages to the GUI for each object shown in the GOP window.

Is there an easy way to change this so that only one "delete" message gets sent to the GUI per object? It's easy enough to ignore the extra messages. But it's _way_ easier to maintain and debug when you don't have to track down and analyze two sources of GUI deletions, especially when the dataflow is obscured by function callbacks in C.

-Jonathan