Update graphics library

This fixes a rendering bug in Unbuntu.
05 - Multiple entities

http://stevelosh.com/blog/2012/07/caves-of-clojure-05/
http://stevelosh.com/blog/2012/07/caves-of-clojure-05/#drawing-the-entities
http://stevelosh.com/blog/2012/07/caves-of-clojure-05