Revert "Improve denLib's MD5 hash implementation to be reasonably fast."

This reverts commit b5cb1fda5eb8e3e7264010de73405c7e64fff933.
Scratch that, just return the string input, don't even hash it. I'm not sure what this was supposed to do, but it was being used before using the string in a hashmap and just making it pointlessly slower.

Signed-off-by: Ross Allan <rallanpcl@gmail.com>
Fix #230

Signed-off-by: Ross Allan <rallanpcl@gmail.com>