Update Ring to 1.6.0

Author: weavejester

project.clj

@@ -4,7 +4,7 @@
   :license {:name "The MIT License"
             :url "http://opensource.org/licenses/MIT"}
   :dependencies [[org.clojure/clojure "1.5.1"]
-                 [ring/ring-core "1.6.0-beta5"]]
+                 [ring/ring-core "1.6.0"]]
   :plugins [[lein-codox "0.9.6"]]
   :codox {:project {:name "Ring-Headers"}
           :output-path "codox"}