Adding or deleting MFHD records from the XUL menus requires
coordinating the OPAC display, the XUL menus, and the Serial
Control distribution editors. The previous code frequently
required some non-obvious manual refreshing to make it work.
This commit keeps them in sync using custom events instead.
Signed-off-by: Dan Wells <dbw2@calvin.edu> Signed-off-by: Jason Etheridge <jason@esilibrary.com>