Embed browse plugin

Fixes #29 

Adds embedded browse functionality to an "At the library" show page. JS plugin overwrites the link locations so that non JS browsers will still click through to a link to the browse page.

![screen shot 2014-06-24 at 5 24 36 pm](https://cloud.githubusercontent.com/assets/1656824/3380144/72747400-fbff-11e3-8c9e-59292ef968ef.png)

![screen shot 2014-06-24 at 5 25 01 pm](https://cloud.githubusercontent.com/assets/1656824/3380147/77f0b088-fbff-11e3-8d58-00ee96353829.png)

Left and right browse more boxes with links to the original item browse page.

![screen shot 2014-06-24 at 5 25 08 pm](https://cloud.githubusercontent.com/assets/1656824/3380152/9feeff9a-fbff-11e3-8952-f591d5a881c6.png)

![screen shot 2014-06-24 at 5 25 14 pm](https://cloud.githubusercontent.com/assets/1656824/3380154/a3be71be-fbff-11e3-992f-a8961227b30f.png)


It can be but I did it this way to leave it open to be used elsewhere if we needed with option data attributes. Happy to do it the other way I still need to add an optional parameter `index` to the helper method which kind of gums up the helper method IMHO