I need to tokenize whitespace at the top-level for Selectors.

Author: tabatkins

css3-syntax/Overview.src.html

@@ -253,6 +253,7 @@ <h3>
 		percentage,
 		dimension,
 		unicode-range,
+		whitespace,
 		cdo,
 		cdc,
 		colon,
@@ -350,6 +351,8 @@ <h4>
 	<dl>
 		<dt><i>whitespace</i>
 		<dd>
+			Consume as much <i>whitespace</i> as possible.
+			Emit a whitespace token.
 			Remain in this state.
 
 		<dt>U+0022 QUOTATION MARK (")