[racket] Whalesong 1.9 released

Hi everyone,

Whalesong 1.9 corrects a few issues, particularly the use of external
CSS stylesheets on the Android phone browsers.

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Changes:

    * Added view-has-attr? and remove-view-attr.

    * Added example that shows the use of checkboxes.  See the
"hot-cross-buns" example in
http://hashcollision.org/whalesong/#(part._.Examples)

    * Improved compatibility with web-world and the Android web
browser: external css style sheets should now work.

    * Miscellaneous bug fixes.

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The installation procedure has been amended!

Before you create the launcher, if you are using DrRacket,

    1. Please go to the Racket submenu.
    2. Select the Limit Memory item.
    3. Change the setting to Unlimited.

This is to avoid an installation-time issue that has been preventing
Whalesong from fully installing in the past.  Afterwards, the
procedure is the same: to upgrade, delete the old launcher and install
a new one, as described in the documentation at:

    http://hashcollision.org/whalesong