Mikaël Salson authored Feb 10, 2016 and Vidjil Team committed Feb 10, 2016

The type of message is determined with two variables:
* success either 'true' or 'false' determining if we had an error
* priority by default 1 if success == 'true' and 2 otherwise, can be overridden
  to be 3 (critical error: the user must see the message) or 0 (hidden message).

This is useful for the upload where we want the error message to be seen by the user.