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
document the Hash class
added the HMAC primitive
removed some unwanted imports from R.P.Hash
added length safe version of replicate function
some code and documentation cleanup
fixup hash
added memory buffer to hash cryptographic hashes
added gadget instance for HMAC