"Save as new" should redirect to the created item instead of list view

[Markus Amalthea Magnuson]

Currently, using the "Save as new" button will redirect to the list view, while it would be more useful for it to redirect to the newly created item. This also makes it much easier to create a series of new objects where the next one only differs slightly from the last one.

There is a ticket for this here: https://code.djangoproject.com/ticket/16327

My proposal, based on the suggestions in that ticket, is that we change the default behavior and redirect to the new item instead. Also, we add the option ModelAdmin.save_as_continue (with default value True) so that anyone can revert to the old behavior by setting it to False.

How does that sound?