Adding API's

Adding AFNetworking and PPrYvApiClient. Both don't work because of
version compatibility. Security Backup
Removing useless class from API's

Removed useless classes from AFNetworking and PPrYvApiClient
Implementation of model and note creation

It's a start to the model implementation using CoreData. So far, the
model contains a user that has notes. Notes contains tags and a folder.
Each entity is also obviously composed of basic type attributes (name,
id, token, dates, ...).

Secondly, it is now possible to create a note and add it to the
persistent store. Therefore, the changes are kept from one run to
another.

The menu has also been ordered in a better, more logical way.
Trashed files

Files that are or useless or has been moved.
Last pryved items

Changed the "Las pryved items" menu by a submenu that displays the last
items instead of including them in the main menu.

(inspired by Dropbox)