The sun trajectory calculation previously emitted garbage if midnight
sun or polar night phenomena was in effect. To fix this, the calculation
is overhauled to report if the computation failed, and if so, which
specific phenomena was the cause.
Timing recalulation uses this information to change out of the normal
state that uses the four sun position timings, into a static state where
wlsunset simply waits a day at a time for a normal sun trajectory
pattern to be restored. In this state, a fixedc high/low temperature is
set as appropriate for the phenomena.
A transition phase replicating the previous day's sunrise is used to
smooth out entry into a midnight sun, which would otherwise cause a
jarring instant-daylight setting.