Adding support for link state to GUI.

Change-Id: I6476cf04810f7bc7e88af629a36ce671b42748d0
diff --git a/web/gui/src/main/webapp/topo2.js b/web/gui/src/main/webapp/topo2.js
index f34f247..5329545 100644
--- a/web/gui/src/main/webapp/topo2.js
+++ b/web/gui/src/main/webapp/topo2.js
@@ -826,7 +826,7 @@
         // merge in remaining data
         $.extend(lnk, link, {
             class: 'link',
-            svgClass: type ? 'link ' + type : 'link'
+            svgClass: (type ? 'link ' + type : 'link') + ' ' + (link.online ? 'active' : 'inactive')
         });
         return lnk;
     }