Issue 351: Reimplement OAuth2 - Step 2 (Auth PCL - only data types)

Src/GoogleApis.Auth/OAuth2/Requests/AuthorizationCodeRequestUrl.cs

Index: Src/GoogleApis.Auth/OAuth2/Requests/AuthorizationCodeRequestUrl.cs
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new file mode 100644
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 b/Src/GoogleApis.Auth/OAuth2/Requests/AuthorizationCodeRequestUrl.cs
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 /*
 Copyright 2013 Google Inc
 Licensed under the Apache License, Version 2.0 (the "License");
 you may not use this file except in compliance with the License.
 You may obtain a copy of the License at
 http://www.apache.org/licenses/LICENSE-2.0
 Unless required by applicable law or agreed to in writing, software
 distributed under the License is distributed on an "AS IS" BASIS,
 WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 See the License for the specific language governing permissions and
 limitations under the License.
 */
 using System;
 using System.Collections.Generic;
 using System.Linq;
 using System.Text;
 using Google.Apis.Requests;
 using Google.Apis.Requests.Parameters;
 namespace Google.Apis.Auth.OAuth2.Requests
 {
 /// <summary>
 /// OAuth 2.0 request URL for an authorization web page to allow the end user to authorize the application to
 /// access their protected resources and that returns an authorization code, as specified in
 /// http://tools.ietf.org/html/rfc6749#section-4.1.
 /// </summary>
 public class AuthorizationCodeRequestUrl : AuthorizationRequestUrl
 {
 /// <summary>
 /// Constructs a new authorization code request with the specified URI and sets response_type to <c>code</c>.
 /// </summary>
 public AuthorizationCodeRequestUrl(Uri authorizationServerEncodedUrl)
 : base(authorizationServerEncodedUrl)
 {
 ResponseType = "code";
 }
 /// <summary>Creates a <seealso cref="System.Uri"/> which is used to request the authorization code.</summary>
 public Uri Build()
 {
 var builder = new RequestBuilder()
 {
 BaseUri = AuthorizationServerEncodedUrl
 };
 ParameterUtils.InitParameters(builder, this);
 return builder.BuildUri();
 }
 }
 }