[plt-dev] Release Announcement for v4.2.2

The release announcement sketch that I have so far is below.  Please
mail me new items and/or edits.

Specifically pinging: Matthias/Robby (htdp), Kathy (test-engine), and
Ryan (syntax/parse).

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* DrScheme now, by default, compiles all of the files that are
  loaded when it runs a program and saves the compiled files in the
  filesystem.  This should lead to faster load times (not faster
  runtimes) since it avoids re-compiling files whose dependencies
  have not changed.

* New Scribble libraries and documentation make it easier to get
  started with Scribble, especially for uses other than PLT
  documentation.  DrScheme now has better indentation and syntax
  coloring support for Scribble languages (and generally all @-exp
  based languages).

* Added support for abstract contracts via the #:exists keywords.
  This is an experiment to add support for data hiding to the
  contract system.

* Added `in-producer': a sequence expression makes it easy to
  iterate over producer functions (e.g., `read').  A new
  `scheme/generator' library creates generators that can use a
  (parameterized) yield function.

* A number of changes were made to the DeinProgramm / DMdA language
  levels: The `check-property' and `contract' forms were added,
  `define-record-procedures-parametric' has changed.  See the
  documentation for details.

* ProfessorJ (and related code) is no longer included in the PLT
  distributions.  It may re-appear in the future as a PLaneT package.



* test-engine changes
  - Change to behavior in interactions window. Option 1 implemented.
  - Turning off the nag

* New stuff in `syntax/parse'
  Also `syntax/keyword'?
  `stxclass' collection gone

* htdp changes
  - added last-picture option to stop-when
  - added make-pair to beginner
  - added state display to world programs
  - re-directed image
  - run-simulation -> animate

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