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.
Rather than this being a two line method, would it break anything to do contrib.changeKind(KIND.person) to update the attribute?

It seems that this action should be a single atomic call.