Keep your computer awake! Prevents that your computer activates sceensaver, turns off screen(s) or goes to hibernate when not actively used for a while. Click the indicator icon once to keep your computer awake for the current session. Click again to keep it awake also between restarts (indicated by a small lock icon on the indicator). Clicking again to not keep awake.

Extension Homepage

https://github.com/jenspfahl/KeepAwake