patch applied (cabal-install): Add new InstallPlan type

Mon Apr 14 10:19:14 PDT 2008 Duncan Coutts * Add new InstallPlan type This is joint work with Kolmodin. An InstallPlan records what we want to install and records the outcome of installing packages. It has a fairly strict internal invariant which should guarantee that each package can be configured sucessfully. A ./Hackage/InstallPlan.hs View patch online: http://darcs.haskell.org/cabal-install/_darcs/patches/20080414171914-adfee-a...