Making compatible with Racket's packaging conventions

Added a miniKanren collection as explained here:
http://docs.racket-lang.org/pkg/Package_Concepts.html

Basically, I just moved the files into a subdirectory which allows me to:

1. raco pkg install github://github.com/xmlblog/Racket-miniKanren/master
2. (require miniKanren/mk)

You can test with my fork if you like, but the idea would be that your repository be directly installable as a Racket package. Cheers!

Signed-off-by: Christian Romney <cromney@pointslope.com>