patch applied (ghc): Refactoring, tidyup and improve layering

[Simon Marlow]

Wed May  2 06:54:34 PDT 2007  Simon Marlow <simonmar at microsoft.com>
  * Refactoring, tidyup and improve layering
  
  The stack of breakpoint resume contexts is now part of the
  InteractiveContext and managed by the GHC API.  This prevents misuse
  of the resume context by the client (e.g. resuming a breakpoint that
  isn't the topmost, which would lead to a confused IC at the least).
  
  I changed the TypeEnv in the IC to a [Id].  It only contained Ids
  anyway, and this allows us to have shadowing, which removes an ugly
  and annoying restriction.
  
  The parts of the GHC API which deal with interactive evaluation are
  now in a module of their own, InteractiveEval.
  

    M ./compiler/ghci/ByteCodeInstr.lhs -1 +1
    M ./compiler/ghci/Debugger.hs -15 +11
    M ./compiler/ghci/GhciMonad.hs -27
    M ./compiler/ghci/InteractiveUI.hs -74 +69
    M ./compiler/main/GHC.hs -512 +18
    M ./compiler/main/HscMain.lhs -6 +5
    M ./compiler/main/HscTypes.lhs -25 +30
    A ./compiler/main/InteractiveEval.hs
    A ./compiler/main/InteractiveEval.hs-boot
    M ./compiler/typecheck/TcRnDriver.lhs -14 +10