Previously gnome-shell listened on the Xft Xsettings via GTK+s
GtkSettings to get the font DPI setting. The Xsetting might not
be what we want, and we should not rely on Xsettings when we don't need
to, so lets manage it ourself.
https://bugzilla.gnome.org/show_bug.cgi?id=765011
Window scaling is a clutter feature used to enable automatic scaling of
stage windows when running under as an application in windowing system.
Clutter in mutter does not support running as a stand-alone application
toolkit, so lets remove this unused feature.
https://bugzilla.gnome.org/show_bug.cgi?id=777732
Clutter's evdev input backend has no support for setting double
click timeout set by gnome-settings-daemon. This results in
touchpad click events timing out on wayland, because the
default timeout value wasn't enough.
This patch moves timeout setting to mutter and removes X11
backend specific setting from clutter.
https://bugzilla.gnome.org/show_bug.cgi?id=771576
