Added modular-exponentiation (montgomery ladder) with tests & benchmarks
Merge reference implementation of BLAKE256 added.
Merge Montgomery ladded for slow exponentiation.
got rid of exception raising function runWrite.
ran stylish haskell on Raaz.Core.Write
better documentation for the Rounding class
added x-length branch to travis builds
Adding Blake to Checksum Program fixes #156
script to build raaz for travis