patch applied (cabal): Update UTF8 code

[Ross Paterson]

On Tue, Apr 22, 2008 at 08:07:31AM -0700, Duncan Coutts wrote:
> Tue Apr 22 07:15:39 PDT 2008  Duncan Coutts <duncan at haskell.org>
>   * Update UTF8 code
>   Some code and test cases taken from the utf8-string package.

Can you push this to 1.4?  I've been using a custom hacked version
for hackageDB to make it reject isolated high bytes.  It would be
great if the released Cabal rejected them too.