Freeze break request for gnome-control-center and gnome-desktop

[Bastien Nocera <hadess hadess net>]

https://bugzilla.gnome.org/show_bug.cgi?id=655041
contains 3 patches.

One that adds a simple new function to gnome-desktop, one to add the
"Refresh Rate" drop-down to the display dialogue (which adds a new
string), and one to reduce the number of confusing frequencies from the
list (which adds 2 new strings that are unlikely to be translated for
most languages).

The drop-down looks like this:
https://bug655041.bugzilla-attachments.gnome.org/attachment.cgi?id=324127
though it will say "NTSC" instead of "ATSC" now, as it is a more
recognisible term.

This hasn't received UI review, but the changes are limited, and won't
stop us from providing the same functionality in a different way[1] in
the future.

Cheers

[1]: As noted in https://bugzilla.gnome.org/show_bug.cgi?id=655041#c6