patch applied (packages/base): Add array fusion versions of map, filter and foldl

[Don Stewart]

Thu May  4 23:08:58 PDT 2006  dons at cse.unsw.edu.au
  * Add array fusion versions of map, filter and foldl
  
  This patch adds fusable map, filter and foldl, using the array fusion
  code for unlifted, flat arrays, from the Data Parallel Haskell branch,
  after kind help from Roman Leshchinskiy, 
  
  Pipelines of maps, filters and folds should now need to walk the
  bytestring once only, and intermediate bytestrings won't be constructed.
  

    M ./Data/ByteString.hs -49 +191
    M ./Data/ByteString/Char8.hs +11