accessx-status: Add GTK3 support

https://git.gnome.org/browse/gnome-applets/commit/accessx-status?id=cd5250ed5d9aa467a34a6da1e2f566c191b25ca8
https://git.gnome.org/browse/gnome-applets/commit/accessx-status?id=5b91de8cfdd3578a1219d5367354798fbb4b48d3
https://git.gnome.org/browse/gnome-applets/commit/accessx-status?id=724533eefaec3268bc9787a1e146afbee171cf46
cpufreq: Add GTK3 support

https://git.gnome.org/browse/gnome-applets/commit/cpufreq?id=6fd55674cdb0154d26c6d9a78001818cfe44fc58