Edit button now redirects to edit wp instead of show.
wp update looks for optional back url after update.
back_url actually optional. fixes spec.
Twist redirect to back url method to work with JSON params.
Cleanup wp list controller per Hagen's suggestion.
wp details controller informs parent to update back URL
Merge pull request #1801 from opf/fix/wp-details-edit-button

Edit button now redirects to edit wp instead of show.