Add "night" mode

1.3.0

Simplified if

Adds 'demo' mode

Fixed demo mode

- Added note about unix end-of-world date

Adds acceleration

• Orbits in crease in speed depending on button-press duration
• Fix for RTC (getting stuck)
• Adds advanced days in the display (or 'now' if current time)
• Improved documentation

Initial logic

• Initial working solution