v2.1.0

Breaking

• fin no longer declares its own calendar. The FinDate record and its
  six date words are gone; the day-count and bond words now take a JulDate
  from the new julian
  machine. Build one with JulOf(y, m, d) and add Include "julian.shoddy" —
  the arithmetic is unchanged, so prices and yields come out identical.
• At the reckoner prompt, the FINDATE family is now spelled JUL* —
  JULDATE, JULDATEOF and friends, from the new seed. Same date-dict shape,
  so the day-count and bond words take the result exactly as before; only the
  spelling of the making words changed, and a session that tries the old name
  is told the new one.

Added

• machines/julian.shoddy
  — the calendar as arithmetic, and the one place the Gregorian leap rules are
  spelled: checked and total date builders, day arithmetic, weekdays, and the
  two day-number epochs (the 1970 serial and the astronomical Julian day) one
  constant apart. clock gains ClockDate(), the single bridge from "now"
  into that arithmetic.
• machines/ephemeris.shoddy
  — the sky as arithmetic: sidereal time, altitude and azimuth for any
  observer, the sun and the moon as sky positions, the moon's phase, age,
  distance, rise and set, and the five naked-eye planets from Keplerian
  elements. Pure throughout; every word takes a Julian day number.
• seed-julian and seed-ephemeris put both machines at the reckoner
  keyboard — JULDATE and JULDAYNUMBER through EPHMOONRISE — in halifax
  and sparky alike.
• Numeric ODE solving in eng: a fourth-order Runge–Kutta stepper over
  quotations, scalar (EngOdeSolve) and systems (EngOdeSysAt), for the
  motion problems the physics atlas works through.
• docs/charter.html —
  the charter of the mathematical family: which machine owns what, the layer
  map, and the rules that keep alg, eng, fin, geo, julian, ephemeris, lin,
  math, matrix, neural, random and sparse one family rather than a pile.
• docs/physics.html —
  the physics atlas: where each physics topic lives in the tree, with a worked
  damped-driven oscillator.
• Every machine page now opens with a history — "A Brief History of…" as
  part of the intro, from the haversine to the ready reckoner, on all
  forty-three pages instead of seventeen.

Changed

• geo's GeoJulian is now defined over julian's JulDayNumber — one set of
  leap rules in the whole tree, bit-for-bit the same answers.
• The reckoner seeds are listed once, on the
  reckoner page,
  instead of being repeated in every machine's "Who Uses It" — and that
  listing is now ground-truth-checked, both directions.
• geo joined the quick reference's Core numerics table, which it had always
  been missing from.