A Racket interface to bcrypt

This is derived from bcrypt interface from the Python 'cryptacular' library by Daniel Holth, available here: https://bitbucket.org/dholth/cryptacular/

Includes the C sources for a version of bcrypt, which are compiled as part of raco setup bcrypt. The version of bcrypt is by Solar Designer, and is available here: http://www.openwall.com/crypt/

Available under the MIT license.