Add POST support to XHR as well as .status and statusText support

sky/tests/framework/xmlhttprequest/empty-responseType.sky

Index: sky/tests/framework/xmlhttprequest/empty-responseType.sky
diff --git a/sky/tests/framework/xmlhttprequest/empty-responseType.sky b/sky/tests/framework/xmlhttprequest/empty-responseType.sky
index 19a132b55124b65e9673012491119b06bbfd8278..f97e25433640389fef82e110fa6192bdb7ad1f1b 100644
--- a/sky/tests/framework/xmlhttprequest/empty-responseType.sky
+++ b/sky/tests/framework/xmlhttprequest/empty-responseType.sky
@@ -4,9 +4,7 @@
 <import src="/sky/framework/xmlhttprequest.sky" as="XMLHttpRequest" />
 <script>
 describe("xmlhttprequest.responseType", function() {
-  this.enableTimeouts(false);
-
-  it("should default to text when empty", function() {
+  it("should default to text when empty", function(done) {
     var xhr = new XMLHttpRequest();
     assert.equal(xhr.responseType, "");
     xhr.responseType = 'foo';