Fix broken link for Clojure logo

Prior to this commit the clojure logo gif resulted in a 404 from
wikipedia. This commit fixes that by using the current clojure logo gif
from the clojure wikipedia entry.
Update clojure logo file name in example block

This commit updates the file name in the texture code block to reflect
the updated URL from wikipedia.
Merge pull request #61 from briancain/master

Fix broken link for Clojure logo