[plt-scheme] Notable bug-fix in uri-codec.ss in the net collection

The library uri-codec.ss in the net collection has been updated in both exp 
and v299. It is not possible to create a URL with ampersands (`&') in it and 
then use that URL in a XML page created with the xml collection; the 
ampersands would instead be escaped to `&'. We have removed the problem 
by following the advice at 

 http://www.w3.org/TR/html401/appendix/notes.html#ampersands-in-uris

Instead of using & to separate query pairs in URLs, we now recommend and 
parse semicolons (`;'). For example, instead of

 http://www.example.com/search?q=the+query&lang=en

now use

 http://www.example.com/search?q=the+query;lang=en

-- 
Mike Burns netgeek at speakeasy.net http://mike-burns.com