Add a unuque identifier for installed packages (part 4 of 9)
Add a unuque identifier for installed packages (part 4 of 9)

Distribution.Simple.LocalBuildInfo: 

  - the LocalBuildInfo record contains an index of the installed
    packages; this has changed from PackageIndex InstalledPackageInfo
    to InstalledPackageIndex.

  - ComponentLocalBuildInfo stores the "external package dependencies"
    of the component, which was 
      componentPackageDeps :: [PackageId]
    and is now
      componentInstalledPackageDeps :: [InstalledPackageId]

  - we now export
      componentPackageDeps :: LocalBuildInfo -> [PackageId]
    (since to get the PackageId for an InstalledPackageId, you need
    to look it up in the InstalledPackageIndex, which is in the
    LocalBuildInfo)

  - similarly, previously
      externalPackageDeps :: LocalBuildInfo -> [PackageId]
    is now
      externalPackageDeps :: LocalBuildInfo -> [InstalledPackageId]

thomie/cabal,Helkafen/cabal,rimmington/cabal,enolan/cabal,ghc-android/cabal,fpco/cabal,martinvlk/cabal,anton-dessiatov/cabal,gridaphobe/cabal,thomie/cabal,Peaker/cabal,typelead/epm,Helkafen/cabal,mmakowski/cabal,gbaz/cabal,fugyk/cabal,kosmikus/cabal,enolan/cabal,trskop/cabal,triplepointfive/cabal,sopvop/cabal,fugyk/cabal,themoritz/cabal,x-y-z/cabal,lukexi/cabal,edsko/cabal,sopvop/cabal,corngood/cabal,valderman/cabal,mydaum/cabal,ian-ross/cabal,alphaHeavy/cabal,seereason/cabal,lukexi/cabal,triplepointfive/cabal,mmakowski/cabal,gridaphobe/cabal,thoughtpolice/cabal,trskop/cabal,randen/cabal,randen/cabal,thoughtpolice/cabal,x-y-z/cabal,gbaz/cabal,christiaanb/cabal,mydaum/cabal,beni55/cabal,garetxe/cabal,martinvlk/cabal,valderman/cabal,Heather/cabal,mightybyte/cabal,seereason/cabal,kosmikus/cabal,plumlife/cabal,edsko/cabal,Peaker/cabal,plumlife/cabal,kolmodin/cabal,corngood/cabal,kolmodin/cabal,plow-technologies/cabal,bennofs/cabal,themoritz/cabal,beni55/cabal,themoritz/cabal,bennofs/cabal,ian-ross/cabal,alphaHeavy/cabal,eric-stanley/cabal,plow-technologies/cabal,mightybyte/cabal,anton-dessiatov/cabal,typelead/epm,christiaanb/cabal,Heather/cabal,garetxe/cabal,eric-stanley/cabal,ghc-android/cabal,headprogrammingczar/cabal,headprogrammingczar/cabal,rimmington/cabal,sopvop/cabal,fpco/cabal