mate-appearance-properties: "Customize Theme": A "Notifications" tab is missing

[davidhedlund]

Expected behaviour

• A "Notifications" tab present in the "Customize Theme". Because the theme entry in mate-appearance-properties -> Theme [tab], is selected only if /org/mate/notification-daemon/theme and the rest of the items found in "Customize Theme" are set to the values that belong to the theme.
• Add -p notifications to mate-appearance-properties, and document the option to man mate-appearance-properties.

Actual behaviour

There is no "Notifications" tab present in the "Customize Theme"

Steps to reproduce the behaviour

In Trisquel 11

• Run dconf watch / in a terminal
• Open mate-appearance-properties. Change the theme to "BlackMATE" and then to "BlueMenta"
• dconf watch / output

  
  /org/mate/desktop/interface/gtk-theme
  'BlackMATE'

/org/mate/marco/general/theme 'BlackMATE'

/org/mate/notification-daemon/theme 'coco'

/org/mate/desktop/peripherals/mouse/cursor-theme 'mate'

/org/mate/desktop/interface/gtk-theme 'BlueMenta'

/org/mate/notification-daemon/theme 'slider'

/org/mate/marco/general/theme 'BlueMenta'

/org/mate/desktop/peripherals/mouse/cursor-theme 'mate-black'

* As you can see, `/org/mate/notification-daemon/theme` is involved in the themes.

#### MATE general version
1.26.0

#### Package version
1.26.0

#### Linux Distribution
Trisquel 11

#### Link to bugreport of your Distribution (requirement)
Trisquel is based on Ubuntu MATE. However, there are only Yuru-themes in Ubuntu MATE, which is why I used Trisquel as reference in this issue.

[lukefromdc]

Never has been one all the way back to GNOME 2