Add support for multiple announce servers (fixes #677)

Somebody owes me a beer.

gui/scripts/syncthing/core/directives/popoverDirective.js

@@ -0,0 +1,9 @@
+angular.module('syncthing.core')
+    .directive('popover', function () {
+        return {
+            restrict: 'A',
+            link: function (scope, element, attributes) {
+                $(element).popover();
+            }
+        };
+});