Share the same url for XHR and html form
Use the SharedFile class.

Add a new class named SharedFile (an orm like class) to replace
many functions. This new class will be used to manage uploaded
files (get/save/delete).
[Fix] French translation for the delete page
Use flash messages from Flask
Use POST (instead of GET) to delete a file

When the user clicks the confirmation button to delete a file, we use
the POST method (instead of GET) to post a form to the server. All
requests that change the state of a ressource (like deleting a file)
should only by done with a POST.
Create a SharedFile object in a more secure way
Notify admins when a file is uploaded
Notify admins when a file is deleted
[Fix] 'flaskup' shell command
Display file size in notification mails
Add some configuration checks at startup
Update README