adds ask a librarian functionality

Closes #133 and closes #701 

Has tests for functionality required data attributes in the view, but was conflicted on how to actually test this as it is time dependent on an outside service. I tested it and was able to chat with a librarian.

![screen shot 2014-08-20 at 2 03 27 pm](https://cloud.githubusercontent.com/assets/1656824/3988244/23568800-28ae-11e4-8a8d-4b5b7e991d3b.png)
![screen shot 2014-08-20 at 2 03 38 pm](https://cloud.githubusercontent.com/assets/1656824/3988247/24fdedd8-28ae-11e4-823f-11e7be7f969f.png)
![screen shot 2014-08-20 at 2 03 48 pm](https://cloud.githubusercontent.com/assets/1656824/3988249/27b021e0-28ae-11e4-8b27-7eb2f1512a78.png)

If a non-js browser came here then the link would show as enabled.  Not really a huge deal, but I wonder if it makes sense to have the link in the disabled state (if we're going to have one) and then enable it if the chat service responds as available.

Perhaps (as I mention in my comment below) the disabled state won't be necessary.