(rails3) Fix autosuggest for classes and groups

This pull request fixes two main problems with autosuggest:
 1) broken versions of plugins/dashboard for jQuery 1.9
 2) explicitly removing the root node as part of json serialization.

```json
[ { "node_class": { "created_at":"2013-04-02T22:48:33Z",
                           "id":3,
                           "name":"mike",
                           "updated_at":"2013-04-02T22:48:33Z"}},
  { "node_class": { "created_at":"2013-04-02T23:08:06Z",
                           "id":7,
                           "name":"misanthrope",
                           "updated_at":"2013-04-02T23:08:06Z"}},
  { "node_class": { "created_at":"2013-04-02T23:07:58Z",
                           "id":6,
                           "name":"mistake",
                           "updated_at":"2013-04-02T23:07:58Z"}}]
```
becomes

```json
[ { "created_at":"2013-04-02T22:48:33Z",
     "id":3,
     "name":"mike",
     "updated_at":"2013-04-02T22:48:33Z"},
  { "created_at":"2013-04-02T23:08:06Z",
    "id":7,
    "name":"misanthrope",
    "updated_at":"2013-04-02T23:08:06Z"},
  { "created_at":"2013-04-02T23:07:58Z",
    "id":6,
    "name":"mistake",
    "updated_at":"2013-04-02T23:07:58Z"}]
```

/cc: @sodabrew