removed unwanted imports
renamed Buffer to MemoryBuf
use System.Process instead of depreciated System.Cmd
raaz-random fixed to use MemoryBuf instead of Buffer
some more import cleanup
removed local-rep-clean target from clean
documentation of Raaz.Hash improved
toHex and toBytestring exposed by individual hash modules

If one is interested only in a particular hash then they can use the
corresponding module with all the interfaces avaliable.
stop hlint bitching about import/export shortcut
Added writeByteString