changes to AJAX request for Chrome and FireFox
to render the HTML and not the JSON
move re-calculate total to a "Marionette Application" event aggregator function

if you're asking what the heck?, look at this,
https://github.com/marionettejs/backbone.marionette/blob/master/docs/marionette.application.md#appvent-event-aggregator
move logic into other function call
move logic updating the Taxon from the Product
Detail View to the Spree Wizard Application using
the Marionette Application vent/trigger

More info here,
https://github.com/marionettejs/backbone.marionette/blob/master/docs/marionette.application.md#appvent-event-aggregator