more portable paths in Setup.lhs
fixed package unregistering and reorganized make rules
fixed tests to work with the new implementations
fixed raaz-executables to work with the new implementations
Merge multi-implementation fixed #41 and #44

1. One can define multiple implementations of the same primitive

2. There is a recomended implementation which should hopefully be the
   best implementation to use w.r.t speed or security or both.

3. User can use explicit implementations overiding the one selected as
   the recomended implementation.
getting rid of text dependency
moving Hash and MAC modules to Raaz.Primitives
arranging stuff in alphebetic order
fixing raaz-tests
fixed the module name for Raaz.Primitives.Hash
reorganized the modules for SHA1 hash
reorganising the modules for SHA256 and SHA224 hashes
reorganising the modules for SHA512 and SHA384 hashes
deleting Raaz.Hash.Sha module
fixed the cabal exports
fixing the module names in sha tests
fixed raaz-executable
fixed Sha utils module
inline pragma defined for the padding functions
moved instance declarations closer to data declaration for SHA512