Merge pull request android-async-http#275 from usepropeller/request_params_add

Add RequestParams#add

Author: loopj

src/com/loopj/android/http/RequestParams.java

@@ -142,6 +142,22 @@ public void put(String key, ArrayList<String> values)  {
         }
     }
 
+    /**
+     * Adds value to param which can have more than one value.
+     * @param key the key name for the param, either existing or new.
+     * @param value the value string for the new param.
+     */
+    public void add(String key, String value) {
+        if(key != null && value != null) {
+            ArrayList<String> paramArray = urlParamsWithArray.get(key);
+            if (paramArray == null) {
+                paramArray = new ArrayList<String>();
+                this.put(key, paramArray);
+            }
+            paramArray.add(value);
+        }
+    }
+
     /**
      * Adds an input stream to the request.
      * @param key the key name for the new param.