Pubstwo 903 fix

In order for contributors to be updated in the Contributors tab after adding or editing them, we need to load the select2's dynamically. Also meant that the selectOptions needed to be defined for each contributor in the tab.

I also added the message sent when the persistance service returns an 500 error to the Notify window.
This mimics what is done in the DOM. the kind attribute is attached to the select2 so is updated automatically. The changeKind method is called when the select2 changes to update the rest of the attributes.