patch applied (packages/Cabal): Add more to the user guide intro trying to explain the scope and use model

[Clemens Fruhwirth]

Sat Dec  8 08:14:02 PST 2007  Duncan Coutts <duncan at haskell.org>
  * Add more to the user guide intro trying to explain the scope and use model

    M ./doc/Cabal.xml -1 +89