GUACAMOLE-5: Generalize and clean the guacGroupList directive such that arbitrary GroupListItem types can be supported.

guacamole/src/main/webapp/app/home/templates/connectionGroup.html

@@ -1,5 +1,4 @@
 <span class="name">
-
-    <a ng-show="item.isBalancing" ng-href="#/client/{{context.getClientIdentifier(item)}}">{{item.name}}</a>
-    <span ng-show="!item.isBalancing">{{item.name}}</span>
+    <a ng-show="item.balancing" ng-href="#/client/{{context.getClientIdentifier(item)}}">{{item.name}}</a>
+    <span ng-show="!item.balancing">{{item.name}}</span>
 </span>