Adapt to API changes in MateRRScreen

gnome_rr_screen_new does not accept a callback anymore, we need
to use the "screen-changed" signal

Based on gnome-control-center commit: 66e8e903be8ad25fe3b1386d1fbda75359959e97
From: Giovanni Campagna <gcampagna@src.gnome.org>
Adapt to MateDesktop API changes

MateRRScreen, MateRRConfig and MateRROutputInfo (formerly
MateOutputInfo) have turned into opaque GObjects. Use accessors
for modifying them, and allocate/free them as GObjects.

Based on gnome-control-center commit: 3eb3ca4506624fb537c55796d1397eb5f9b8da4b
From: Giovanni Campagna <gcampagna@src.gnome.org>
Update for renamed mate_rr_output_info functions

mate_rr_output_info_get_connected -> mate_rr_output_info_is_connected
mate_rr_output_info_get_active -> mate_rr_output_info_is_active
Adapt to changed signal from screen-changed to changed
[displays] Change panel name to Displays

Monitors aren't the only use of this panel. Projectors and tablet screens don't involve monitors at all.

Based on gnome-control-center commit: e8b52610496818a214cf8b12d955cc4fca40f085
From: William Jon McCann <jmccann@redhat.com>
Bump required mate-desktop version for materr* changes