[racket-dev] skip release

We (release management) are thinking of skipping this release and
wanted to see if anyone minded first. Below is a possible message we
would send to justify this to the external folk.

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Dear Racketeers,

as we are preparing the v5.3 release, we notice unexplored corners
of new and revised features (see bug report #12724, just submitted). 
Two concerns stand out: the addition of sub-modules and the extensive 
injection of contracts into the class hierarchy in our run-time library. 
In short, our changes aren't ready for an actual release.

Since we consider none of the changes critical for any of our users,
we have decided to skip the May release date. Instead, we will
release

Racket version 5.3 in August.

If this delay causes you serious inconveniences, please let us know
privately as soon as possible.

For those users who wish to take advantage of the new features,
please use the nightly builds available from
http://pre.plt-scheme.org. Doing so will help us discover problems
and will help you transition to the new release early.

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Thoughts and comments appreciated -- Matthias