made cart_record removal and emptying the cart ajax
 - unfortunately, the default jquery_ujs behavior using remote: true on the link
   does NOT work.  If you have multiple links (whether they are remote: true or not)
   they ALL get clicked when any one of them is clicked.  I had to roll my own
   ajax call
added classes to the tr and links to facilitate the unobtrusive javascript
added a js response to cart_records delete to handle the javascript call
(may not have been necessary, but it was in the documentation)