fixed bug which caused links to disappear after being added
only show label when mouse over a switch.
better colors
merge from master
diff --git a/web/ons-demo/js/utils.js b/web/ons-demo/js/utils.js
index 17100b1..4f6d0c1 100644
--- a/web/ons-demo/js/utils.js
+++ b/web/ons-demo/js/utils.js
@@ -11,4 +11,14 @@
 	}
 
 	return parameters;
+}
+
+function findLink(model, dpid) {
+	var links = [];
+	model.links.forEach(function (link) {
+		if (link['src-switch'] == dpid || link['dst-switch'] == dpid) {
+			links.push(link);
+		}
+	});
+	return links;
 }
\ No newline at end of file