CC-4166: Playlist Builder -> Regular Playlist : clicking Fade in/out button for a empty playlist will cause PHP Fatal Error

- fixed. Not displaying fade setting button if the playst/smartplaylist
is empty.

airtime_mvc/public/js/airtime/library/spl.js

@@ -305,11 +305,19 @@ var AIRTIME = (function(AIRTIME){
 		$('#spl_sortable')
 			.empty()
 			.append(json.html);
-		
 		setModified(json.modified);
 		redrawLib();
 	}
 	
+	function setFadeIcon(){
+	    var empty = $(".spl_empty");
+	    if (empty.length > 0) {
+	        $("#spl_crossfade").hide();
+	    } else {
+	        $("#spl_crossfade").show();
+	    }
+	}
+	
 	function getId() {
 		return parseInt($("#obj_id").val(), 10);
 	}
@@ -803,6 +811,7 @@ var AIRTIME = (function(AIRTIME){
 		}
 		else {
 			setPlaylistContent(json);
+			setFadeIcon();
 		}
 		
 		mod.enableUI();