misc::Calculator works a typed sum in forms::evaluate's precedence,
from a pad or the keyboard; Enter is equals while the calculator
itself has focus, and Escape clears or passes on. misc::UnitConverter
reads an amount in another unit across seven kinds, with a swap.
Both show numbers through format::significant, which rounds through
Rust's exponent form.
misc::Clock shows the time in a zone, the system's unless told, as an
analog face with hour marks and three hands over its digits and a
label; it wakes its view at each whole second of the wall clock, and
only while the owner passes no moment. misc::WorldClock lays places in
rows: a small face, the place, how its day and hour stand against home,
and its time. misc::Stopwatch runs on the executor's clock in tenths,
holds while paused, marks laps while running and clears once paused;
Start and Pause share one button and its focus.
ZacharyZhang-NY