Expose RequestBuilder reset methods, close AsyncHttpClient#515

Author: Stephane Landelle

src/main/java/com/ning/http/client/RequestBuilderBase.java

@@ -458,19 +458,27 @@ public T addCookie(Cookie cookie) {
         return derived.cast(this);
     }
 
-    private void resetParameters() {
+    public void resetQueryParameters() {
+        request.queryParams = null;
+    }
+    
+    public void resetCookies() {
+        request.cookies.clear();;
+    }
+    
+    public void resetParameters() {
         request.params = null;
     }
 
-    private void resetNonMultipartData() {
+    public void resetNonMultipartData() {
         request.byteData = null;
         request.stringData = null;
         request.streamData = null;
         request.entityWriter = null;
         request.length = -1;
     }
 
-    private void resetMultipartData() {
+    public void resetMultipartData() {
         request.parts = null;
     }