ChemDraw DDE Usage

1. Make the DDE connection, using the correct server name ("ChemDraw_Server") and topic.
2. Issue commands such as DLL, EDIT and PIPE. If the client wants a structure edited in ChemDraw, and the result returned, it should first send an EDIT command, following up with an ADVISE loop. If the client does not need the edited structure returned, the OPEN command should be used instead.