Low-to-high animation runs from sunrise to sunrise+duration. However,
high-to-low animation ran from sunset to sunset+duration.
Run high-to-low animation at sunset-duration to sunset.
The compiler is confused by the circular switch, and thinks that temp
might become uniniitalized. This is clearly false, as it is set at all
switch breaks.
Silence the warning by explicitly initializing it to zero.
Add a SPEEDRUN define which, if set, will run wlsunset at 200x
super-realtime to aid testing.
Sleep timing calculations were approximated and often off. These have
been adjusted from testing using the SPEEDRUN feature.