[mediaqueries] Do not allow the <media-query> production to match the empty string, reverting an unintentional change from MQ3

Author: frivoal

mediaqueries/Overview.bs

@@ -690,8 +690,10 @@ Syntax</h2>
 	Note: This explicit definition of <<media-query-list>> parsing
 	is necessary to make the error-recovery behavior of <a>media query lists</a> well-defined.
 
+	Note: This definition of <<media-query-list>> parsing intentionally accepts an empty list.
+
 	<pre>
-	<dfn>&lt;media-query></dfn> = <<media-condition>>?
+	<dfn>&lt;media-query></dfn> = <<media-condition>>
 	             | [ not | only ]? <<media-type>> [ and <<media-condition>> ]?
 	<dfn>&lt;media-type></dfn> = <<ident>>
 

mediaqueries/Overview.html

@@ -60,7 +60,7 @@
 </p>
   <h1 class="p-name no-ref" id=title>Media Queries Level 4</h1>
   <h2 class="no-num no-toc no-ref heading settled" id=subtitle><span class=content>Editor’s Draft,
-    <span class=dt-updated><span class=value-title title=20140913>13 September 2014</span></span></span></h2>
+    <span class=dt-updated><span class=value-title title=20141001>1 October 2014</span></span></span></h2>
   <div data-fill-with=spec-metadata><dl>
 	<dt>This version:
 	<dd><a class=u-url href=http://dev.w3.org/csswg/mediaqueries4/>http://dev.w3.org/csswg/mediaqueries4/</a>
@@ -1157,7 +1157,9 @@ <h2 class="heading settled" data-level=3 id=mq-syntax><span class=secno>3 </span
 <p class=note>Note: This explicit definition of <a class="production css" data-link-type=type href=#typedef-media-query-list title="<media-query-list>">&lt;media-query-list&gt;</a> parsing
 	is necessary to make the error-recovery behavior of <a data-link-type=dfn href=#media-query-list title="media query lists">media query lists</a> well-defined.</p>
 
-	<pre><dfn class=css data-dfn-type=type data-export="" id=typedef-media-query>&lt;media-query&gt;<a class=self-link href=#typedef-media-query></a></dfn> = <a class="production css" data-link-type=type href=#typedef-media-condition title="<media-condition>">&lt;media-condition&gt;</a>?
+<p class=note>Note: This definition of <a class="production css" data-link-type=type href=#typedef-media-query-list title="<media-query-list>">&lt;media-query-list&gt;</a> parsing intentionally accepts an empty list.</p>
+
+	<pre><dfn class=css data-dfn-type=type data-export="" id=typedef-media-query>&lt;media-query&gt;<a class=self-link href=#typedef-media-query></a></dfn> = <a class="production css" data-link-type=type href=#typedef-media-condition title="<media-condition>">&lt;media-condition&gt;</a>
              | [ not | only ]? <a class="production css" data-link-type=type href=#typedef-media-type title="<media-type>">&lt;media-type&gt;</a> [ and <a class="production css" data-link-type=type href=#typedef-media-condition title="<media-condition>">&lt;media-condition&gt;</a> ]?
 <dfn class=css data-dfn-type=type data-export="" id=typedef-media-type>&lt;media-type&gt;<a class=self-link href=#typedef-media-type></a></dfn> = <a class="production css" data-link-type=type href=#typedef-ident title="<ident>">&lt;ident&gt;</a>
 <dfn class=css data-dfn-type=type data-export="" id=typedef-media-condition>&lt;media-condition&gt;<a class=self-link href=#typedef-media-condition></a></dfn> = <a class="production css" data-link-type=type href=#typedef-media-not title="<media-not>">&lt;media-not&gt;</a> | <a class="production css" data-link-type=type href=#typedef-media-and title="<media-and>">&lt;media-and&gt;</a> | <a class="production css" data-link-type=type href=#typedef-media-or title="<media-or>">&lt;media-or&gt;</a> | <a class="production css" data-link-type=type href=#typedef-media-in-parens title="<media-in-parens>">&lt;media-in-parens&gt;</a>