Haskell bindings

These Haskell bindings make large use of c2hs to generate much of the code, so
Unicorn's const_generator is not used.

The emulator is based on the Either monad transformer. The IO monad is used to
run the underlying Unicorn library, while the Either monad is used to handle
errors.

Instructions on how to build the bindings are located in
bindings/haskell/README.TXT. The same samples found in samples/ can be found
in bindings/haskell/samples. They should produce the same output, with slight
differences in their error handling and messaging.

CREDITS.TXT

@@ -60,3 +60,4 @@ Ryan Hileman: Go binding
 Antonio Parata: .NET binding
 Jonathon Reinhart: C unit test
 Sascha Schirra: Ruby binding
+Adrian Herrera: Haskell binding