[plt-scheme] Fwd: Bugs fixed, test suite started

Thanks to Mike Burns for converting the existing test suite to use 
scheme unit and for adding many new test cases.
Test cases have been added to reproduce Bug 6925.
Fix for bug 6925 has been checked in and tagged exp.

Begin forwarded message:

> Bug 6925, "exp-tagged version of web-server is broken 
> (current-directory
> related)", has been fixed. A test suite infrastructure, using 
> SchemeUnit,
> has been put into place.