Trying to get 'lein run' to do something, also started game tutorial.

The 'lein run' command fails because it can't find the class hello_world.core,
maybe it needs to be included somehow? Seems like this would work after out of
the box with 'lein new'.

Started working through a tutorial, got to here:
http://www.lisperati.com/clojure-spels/looking.html