Some Android devices do not include the "Never" timeout option.
Here is a workaround to keep the screen awake as long as it is plugged in and charging: On your device navigate to Settings > Developer Options > and select Stay Awake.
Note: If you don't see Developer options in Settings, it may be made available by going to to Settings > About > Build number. Developer options should appear after tapping the build number several times.
UPDATE: VERSION 1.2.0 (RELEASED 8/29/2018) PREVENTS SCREEN TIMEOUT