Device won't wakeup from power button
If you unlock the developer options (if not already unlocked with Cyanogenmod), there is an option "Stay awake" that will keep your screen turned on when plugged in.  You can try using that and see if it will revert any settings that the app might have changed.

See this website for a brief explanation on how to enable developer options.

If that doesn't work, you can "remap" the power button back to the power button.  Check out this guide to remap the buttons on your phone.  Hopefully it won't come to this though