[MlMt] sound notifications in Sierra

[Ted Byfield]

With the update to "macOS" 😐 Sierra, Mailmate (v 1.9.5 - 5263 and 
then 5268) has started giving sound notifications -- first "glass" and 
then "blow," I think. I've turned them off in two places:

	* System Prefs > Notifications > Mailmate (alert style - none, and all 
checkboxes unchecked), and
	* Mailmate prefs > Counters > Sound pulldown -- x4, one for each 
corner, all are set to "none"

(In passing, that counter UI might be for confusing for users who are 
new and/or less willing/able to put the time in -- but I digress.)

I've also restarted Mailmate, rebooted, etc but my preference don't seem 
to stick completely -- "glass" (or whatever) has gone away but "blow" 
remains," even for messages that are set to mark as "read when I filter 
them.

Any suggestions about how to make it stop would be warmly welcome. 
Thanks!

Cheers,
T