darcs patch: Add a new checkout Command (and 1 more)

Hi, the small feature implemented by the attached patches could make it more convenient for people to quickly and easily contribute to hackage packages. Do you want me to open a ticket for this or can you appl yit right away? Thanks, Joachim 2 patches for repository http://darcs.haskell.org/cabal-install: Sun Nov 7 12:35:32 CET 2010 Joachim Breitner * Add a new checkout Command Given a package name, this uses the SourceRepo field of the newest versionf of that pacakge to figure out the repository location and calls the right VCS invocation. Sun Nov 7 12:43:35 CET 2010 Joachim Breitner * Add a --dry-run flag to cabal checkout