Poisson Prove 0.2.0

Changed

• diff reads in plain words by default: the verdict block, then one table of the conditions in
  the order of their axis values, each with its change and the smallest rise and fall it could
  have detected, and what the comparison left out, in words. The machine sections (the per-event
  tables by hash, the coverage table, the omnibus, the fault lines and the bound) moved behind
  --full, which prints what diff printed before. A tool that read them from the text passes
  --full or reads --json, which did not change.
• Saved comparison ids change at this minor: an id hashes the tool's major and minor version, so
  the same comparison saved again under 0.2.0 gets a new id. Comparisons saved by 0.1.x stay
  readable.
• inspect prints identical errors as one traceback with a count of the episodes that have it,
  each listed episode on a line of its own under it; an error none of the listed episodes has is
  counted in one line. --json is unchanged.
• The dashboard's comparison page shows its heatmaps on the first screen, between the verdict's
  detail lines and what the verdict rests on; the differences and limits charts stay after the
  conditions.
• The limits line of diff, check, report, the dashboard and the terminal app counts the
  rows with no limit by direction, so a row with no limit on its fall is not said to have none on
  its rise; "no change of any size" is said only of a row with no limit either way.
• The look file gains the banner section the Poisson Labs tools share, and its static UI's type
  rule lets labels (table headers, detail labels, captions) take the system's sans.