Added support for class selectors and class attribute selectors on XML documents. Fixes jQuery bug #4167.

test/data/test.js

@@ -1,3 +1,3 @@
-foobar = "bar";
+var foobar = "bar";
 jQuery('#ap').html('bar');
 ok( true, "test.js executed");

test/data/test2.html

@@ -1,5 +1,5 @@
 <script type="text/javascript">
-testFoo = "foo";
+var testFoo = "foo";
 jQuery('#foo').html('foo');
 ok( true, "test2.html executed" );
 </script>

test/data/with_fries.xml

@@ -6,7 +6,7 @@
 		<jsconf xmlns="http://www.example.com/ns1">
 			<response xmlns:ab="http://www.example.com/ns2">
 				<meta>
-					<component id="seite1">
+					<component id="seite1" class="component">
 						<properties xmlns:cd="http://www.example.com/ns3">
 							<property name="prop1">
 								<thing />