API / Fileadapter: resource response data for create folder request

[dneukirchen]

Steps to reproduce the issue

Try to create a new folder:
POST /administrator/index.php?option=com_media&format=json&task=api.files&path=/
JSON BODY: {name: 'my-folder'}

Expected result

A single resource response (not an array of items) with the data of the newly created folder:

{
  success: true,
  message: null, 
  messages: null, 
  data: {
    type: "folder", 
    name: "my-folder", 
    path: "/my-folder", 
    extension: "", 
    size:…
  }
}

Actual result

The contents of the newly created folder.

{success: true, message: null, messages: null, data: []}

[dneukirchen]

Quick and dirty solution: 7f87259

[laoneo]

This should be fixed with PR #96.