script to build platform specific make files

We use make file constraints to make sure that builds use a particular
version of GHC and the assocated packages. The script cabal-config is
now renamed to platform to do the necessary stuff.
rearranging platform files

- moved all cabal files to the cabal subdirectory
- got rid of the cabal.config files
Added Makefile.configure platforms

- haskell-2012.2.0.0
- haskell-2013.2.0.0
removed ghc version description from cabal configurations
Makefile now includes platform specific configurations
got rid of the local-repo

- Now installs from the package tarballs directly.
- No more tinkering with cabal config files.