changed defn of Request and ResponseInit

Request needs to extends Body class and ResponseInit needs to have
statusText and Headers as optional peoperties, corrected typo in test to "basic"

whatwg-fetch/whatwg-fetch-tests.ts

@@ -41,7 +41,7 @@ function test_fetchUrlWithRequestObject() {
 
 function handlePromise(promise: Promise<Response>) {
 	promise.then((response) => {
-		if (response.type === 'basis') {
+		if (response.type === 'basic') {
 			// for test only
 		}
 		return response.text();

whatwg-fetch/whatwg-fetch.d.ts

@@ -5,7 +5,7 @@
 
 /// <reference path="../es6-promise/es6-promise.d.ts" />
 
-declare class Request {
+declare class Request extends Body {
 	constructor(input: string|Request, init?:RequestInit);
 	method: string;
 	url: string;
@@ -69,10 +69,10 @@ declare class Response extends Body {
 
 declare enum ResponseType { "basic", "cors", "default", "error", "opaque" }
 
-declare class ResponseInit {
+interface ResponseInit {
 	status: number;
-	statusText: string;
-	headers: HeaderInit;
+	statusText?: string;
+	headers?: HeaderInit;
 }
 
 declare type HeaderInit = Headers|Array<string>;