devtimer / TODO
- Cleanups:

  - Check to make sure out of range temps still handled properly
  - Improve out of range notification

- Autodetect temp probe device
- Generate compensation tables at startup based on low/hi range - perhaps limited by times <400ms
- Speed up boot time by removing all unneeded boot activity
- Package into a preconfigured DD image for release simplicity
- Longer term: Move to an SPI based set of displays for better rendering speed.