use current ceta (2.39), document how to update ceta

[jwaldmann]

How to update: get source from http://cl-informatik.uibk.ac.at/software/ceta/src/CeTA.tgz Beware - it unpacks to CeTA-2.39 (currently). The relevant sources are in CeTA-2.39/generated/Haskell/

I will put this in the cabal file:

library
  hs-source-dirs: CeTA-2.39/generated/Haskell
  exposed-modules:   Ceta, Array, Data_Bits, IArray, Uint, Uint32, Uint64
  build-depends: base, array

executable ceta-postproc
  hs-source-dirs:         src 
  main-is:             Main.hs
  build-depends:       base, ceta-postproc, parsec, clock

then ideally, updating CeTA is just

• unpack source
• change one line hs-source-dirs in cabal file