Moved disk space and about to new info tab

New: Disk space visible in the UI under System Info

src/UI/System/Info/DiskSpace/DiskSpaceCollection.js

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