How do I autostart devilspie under F21 w/ gnome3?

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I created a devilspie.desktop file in ~/.config/autostart, but it does not start when I log in. My goal is to have an embedded terminal on my desktop. Terminal starts, but not devilspie.

There is no option to manually add an autostart application under gnome-tweak-tool, and gnome-session-properties does not exist and can't be installed from any of the repos.