Don't use light-locker.
Don't use light-locker.

It doesn't return non-zero if it fails to lock the screen, e.g. if
the daemon isn't running.

Use gnome-screensaver, and fall back to xdg-screensaver instead.
We still can't use only xdg-screensaver, since it doesn't work
correctly in XFCE on Ubuntu 14.04.

mikelward/scripts,mikelward/scripts,mikelward/scripts