Replace the form decoder with URLCodec

- This addresses the following URLdecoding issue
ring-clojure/ring#269

src/ring/util/codec.clj

@@ -4,18 +4,19 @@
   (:import java.io.File
            java.util.Map
            [java.net URLEncoder URLDecoder]
-           org.apache.commons.codec.binary.Base64))
+           org.apache.commons.codec.binary.Base64
+           org.apache.commons.codec.net.URLCodec))
 
 (defn assoc-conj
   "Associate a key with a value in a map. If the key already exists in the map,
   a vector of values is associated with the key."
   [map key val]
   (assoc map key
-    (if-let [cur (get map key)]
-      (if (vector? cur)
-        (conj cur val)
-        [cur val])
-      val)))
+         (if-let [cur (get map key)]
+           (if (vector? cur)
+             (conj cur val)
+             [cur val])
+           val)))
 
 (defn- double-escape [^String x]
   (.replace (.replace x "\\" "\\\\") "$" "\\$"))
@@ -58,9 +59,9 @@
   encoding or UTF-8 by default."
   [unencoded & [encoding]]
   (str/replace
-    unencoded
-    #"[^A-Za-z0-9_~.+-]+"
-    #(double-escape (percent-encode % encoding))))
+   unencoded
+   #"[^A-Za-z0-9_~.+-]+"
+   #(double-escape (percent-encode % encoding))))
 
 (defn ^String url-decode
   "Returns the url-decoded version of the given string, using either a specified
@@ -112,7 +113,8 @@
   or UTF-8 by default."
   [^String encoded & [encoding]]
   (try
-    (URLDecoder/decode encoded (or encoding "UTF-8"))
+    (let [codec (URLCodec. (or encoding "UTF-8"))]
+      (.decode codec encoded))
     (catch Exception _ nil)))
 
 (defn form-decode