[plt-dev] Release Announcement for v4.2.4

Possible release announcement items below.  Please mail me new items
and edits or deletions.
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* [Matthew] scheme/fixnum, scheme/flonum, flvectors

* [Matthew] Unsafe stuff (make it's ready to describe now?)

* [Stevie] new `this%'

* [Matthias] `error' in teaching languages?  universe/world changes?
  `random', `gensym', `current-millisecond', `sleep', `assoc',
  `with-i/o-from-to' added?

* [John] New `infinite-generator'`sequence->generator'
  `sequence->repeated-generator'?

* [Carl] contract changes?  (r17105)

* [Carl] New $PLTADDONDIR, `--addon'/`-A' flags?

* [Eli] Much improved `sort' speed.

* [Robby] User-defined keybindings now override menu items (r17135)

* [Robby] New image work?

* [Sam] Typed Scheme changes? (r17281, r17284, r17519, r17520,
  r17551, r17567, r17568, r17575, r17609, r17612, r17653, r17654,
  r17657, r17660)

* [Matthew/Eli] `#:save-errno'?

* [Robby] normalized the results of `procedure-arity'?

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-- 
          ((lambda (x) (x x)) (lambda (x) (x x)))          Eli Barzilay:
                    http://barzilay.org/                   Maze is Life!