make preview image clickable even if no videos are released if you are a mod

templates/macros.html

@@ -212,7 +212,7 @@ $('#embedcodebtn').popover(
 	<div class="row">
 		{% if ismod() or (videos|length > 0) %}
 			<div style="background-image: url('{{ config.VIDEOPREFIX }}/thumbnail/l_{{lecture.id}}.jpg')" class="col-sm-2 col-xs-12 thumbnailimg">
-			{% if not videos|length is equalto 0 %}
+			{% if (not videos|length is equalto 0) or ismod() %}
 				<a href="{{url_for('lecture', course=lecture.course.handle, id=lecture.id)}}">
 					<span class="glyphicon glyphicon-play-circle playpreviewbtn"></span>
 				</a>