* dbusbind.c (xd_read_message): Generate an event for every

* dbusbind.c (xd_read_message): Generate an event for every
registered handler.  There might be several handlers registered
for the same signal.
(Fdbus_register_signal): Don't overwrite a registration for the
same signal.  Add a new registration if handlers are different.
(Vdbus_registered_functions_table): Rework doc string.