* This change removes the external dependency on OpenSSL, which should
allow the code to compile on Mac OS X without specifying the
MAC_OS_X_VERSION_MIN_REQUIRED non-sense.
* Spookyhash should be faster than SHA-1's Merkle-Damgård construction.
* Spookyhash is only 128-bits as opposed to SHA-1's 160-bits so memory
consumption should be less. I doubt it will lead to too many
collisions.
* The docs are updated to reflect the fact that OpenSSL is not a
dependency.
