Support nexted comments in API.

Update findAllByProjectID to return an array with child comments
nested into the 'children' field of the parent.

The result will look like this:

{
  "comments": [
    {
      "projectId": 1,
      "taskId": null,
      "parentId": null,
      "userId": 1,
      "value": "Foo",
      "id": 1,
      "createdAt": "2013-08-10T17:58:16.000Z",
      "updatedAt": "2013-08-10T17:58:16.000Z",
      "children": [
        {
          "projectId": 1,
          "taskId": null,
          "parentId": 1,
          "userId": 1,
          "value": "nested1",
          "id": 4,
          "createdAt": "2013-08-10T18:02:15.339Z",
          "updatedAt": "2013-08-10T18:02:15.339Z"
        },
        {
          "projectId": 1,
          "taskId": null,
          "parentId": 1,
          "userId": 1,
          "value": "nested2",
          "id": 5,
          "createdAt": "2013-08-10T18:02:30.508Z",
          "updatedAt": "2013-08-10T18:02:30.508Z"
        }
      ]
    },
    {
      "projectId": 1,
      "taskId": null,
      "parentId": null,
      "userId": 1,
      "value": "Bar",
      "id": 2,
      "createdAt": "2013-08-10T17:58:19.000Z",
      "updatedAt": "2013-08-10T17:58:19.000Z"
    },
    {
      "projectId": 1,
      "taskId": null,
      "parentId": null,
      "userId": 1,
      "value": "Baz",
      "id": 3,
      "createdAt": "2013-08-10T17:58:22.000Z",
      "updatedAt": "2013-08-10T17:58:22.000Z"
    }
  ]
}
Merge branch 'sprint3' of github.com:Innovation-Toolkit/midas into sprint3