Add data and title attributes to Stanford Only files.

Begins work on #62. Still need to add popover/tooltip styling/behavior but this adds the data and attributes necessary to make that happen. (implemented as a simple title attribute currently)

In the future we can instantiate the tooltip based on the `data-sul-embed-tooltip` attribute "true":

    $('[data-sul-embed-tooltip="true"]').whateverTooltipPlugin();

### Stanford Only Example (tn148pd5374)
![tn148pd5374](https://cloud.githubusercontent.com/assets/96776/4670462/5d5da8bc-5577-11e4-82e8-e893744c4258.png)

### Embargo Example (wb383gy5311)
![wb383gy5311](https://cloud.githubusercontent.com/assets/96776/4670463/5d6207fe-5577-11e4-927b-569c0dc213be.png)