Added Disk space information to system.

(cherry picked from commit 91625019378247b1c6ab85afaee23f2855e3298b)

src/UI/System/DiskSpace/DiskSpaceCollection.js

@@ -0,0 +1,8 @@
+'use strict';
+define(['backbone', 'System/DiskSpace/DiskSpaceModel'],
+function(Backbone, DiskSpaceModel) {
+    return Backbone.Collection.extend({
+        url:window.NzbDrone.ApiRoot +'/diskspace',
+        model: DiskSpaceModel
+    });
+});