Add thumbnail viewer to Manage Bookmarks

Finally eliminate end in favour of curval

webif/html/browse/bookmarks/script.js

@@ -1,6 +1,5 @@
 var curval = 0;
 var $slider;
-var end = -1;
 var values;
  
 function toTimeStr(tval) {
@@ -213,8 +212,8 @@ $('#genthumbs').button( { icons: {primary: "ui-icon-zoomin"}, disabled: false }
 	$.get('/browse/thumbnail/mkrange.jim',
 		{
 			'file': file,
-			's':    start+end,
-			'e':    last+end,
+			's':    start+curval,
+			'e':    last+curval,
 			'i':    incr
 		}, function() {
 			$('#thumbs').show();