Various fixes and enhancements:
- implemented "natural sort", such that product ids appear in the order one would expect when alpha sorting
- wrote code to automatically fill in all the product ids, and cleaned up anything it missed by hand
- added a new "product id" sort, and changed the old "product name" sort such that it ignores product ids
- darkened the line separating browse items
- added a title attribute to product names when browsing, so you can still read the ones that get cut off (we may wind up just ditching the ellipsis thing)
