add support to simply load xblock using the same host + sending extra data to student_view

This PR is to:

* Use jquery.xblock in the LMS. So, not having to specify the sessionsId and domain make it easier. We just need to specify {useCurrentHost: true}
* We can also add a data attribute in the options. Those will simply be send as get parameter to the student_view.

I tested the adventure block with the LMS running at `localhost:8000`, and when I do that, it tries to load ooyala videos from `http://localhost/blah/student_view` instead of `localhost:8000`. As a result, the Ooyala blocks fail to load and a jQuery error occurs. 

I think you need to change this line to also incorporate the port number.