Network disconnect

Have some kind of timeout failsafe that will vent the tanks if no control inputs are received for 1 hour while in a pressurised state. Would require a warning before doing so, with the option to cancel. If there is a way to detect disconnection of the client stdin and stdout directly without just listening for keystrokes this would be ideal but don't spend too long researching if you don't find it straight away.
- [ ] Detect disconnect by lack of keystrokes or otherwise
- [ ] Add automatic venting after 1 hour of disconnect if in pressurised state for entire time