Lumenwright 0.3.0

Added

• A stated sky can stand at a tick and ask for the game's look: StatedSky::tick takes a
  StatedTick (time, look, render_distance), set by StatedSky::at. At it the
  environment is sampled at the tick, not at the world's DayTime; quick mode and the
  game's look draw the tick's sunrise glow, moon and stars through the same code as
  Sky::Vanilla; and HQ mode draws the stated look, weighted for SkyLook::ByTime by the
  one sky::day_weight, with StatedSky::hq as Chunky's part. A stated sky at
  Sky::Vanilla's colours and sun draws its frame byte for byte.
• QuickSkyColours::vanilla: the colours Sky::Vanilla derives at a tick, for a caller to
  state.

Changed

• StatedSky and the new StatedTick are #[non_exhaustive]: build them with
  StatedSky::new(quick, hq) and StatedTick::new(time, look). A struct literal of
  StatedSky no longer compiles, so this is a breaking change for 0.2.x. A stated sky at
  no tick (StatedSky::new) draws what 0.2.0 drew, byte for byte.

Not expressed

• Weather: the game's look, under Sky::Vanilla and at a stated tick, draws a clear sky; it
  applies no rain or thunder.