Change view has "Add" label

[jakubste]

When editing an instance, the user sees "Add [model name]" as a page title, despite it only edits an instance and not create a new one.

This is clear looking in ReverseModelAdmin code:

        reverse_admin_context = {
            'title': _('Add %s') % force_text(opts.verbose_name),

and

return self.render_change_form(request, context, form_url=form_url, add=True)
                                                                    ^^^^^^^^

I believe those fragments should be changed based on add variable value.

[daniyalzade]

Fixed with #64 and 2.7.2