patch applied (cabal-install): Implement --installed to 'cabal list'

[Duncan Coutts]

Sat Mar  1 14:27:04 PST 2008  Lennart Kolmodin <kolmodin at gentoo.org>
  * Implement --installed to 'cabal list'
  Adding --installed to 'cabal list' will make it print only packages that are
  installed.

    M ./Hackage/List.hs -10 +25
    M ./Hackage/Setup.hs -11 +42
    M ./Main.hs -4 +10

View patch online:

  http://darcs.haskell.org/cabal-install/_darcs/patches/20080301222704-fdf66-2a9329faada74d9fafcbf5e1c62168db37c36231.gz