Use the parameter_input partial for inventory search

**Ok, it's ready!**

The inventory search page wasn't updated for newer jQuery, so you couldn't add criteria rows to the search page. This PR switches inventory search to use the same parameter_input partial as node and group variables.

~~I have a little bit more hacking to do on this to wire up params['search_params'] from the nodes controller into the view.~~

![Screen Shot 2013-04-29 at 9 59 35 AM](https://f.cloud.github.com/assets/39406/439824/a06a0abc-b0ee-11e2-878c-9f1a026e4d06.png)