Be able to use different hash formats

[Vlix]

Seeing as some algorithms encode the password hashes in different ways, it might be a good idea to add functionality to dictate how the hash will be output (hashPassword) and/or how it will be read (checkPassword).

This will make the interoperability better between different programs/other languages, and thus make it easier for someone to switch to Haskell, or use Haskell to operate on already existing password hashes.

Here's a list of examples of different formats