Newer jquery returns undefined

These fix a couple of bugs I ran into when trying to reuse the spree table structure code.

1. d8c149c - if you don't have an ID assigned to all of your input elements, you'll get a JS error with the newest jQuery because it returns undefined when not finding elements
2. 44c3749 - if you are leveraging this code with select boxes, they won't get the correct ID set and not be POSTed