request-blocking fix, and currentVideo URL support

- I think I fixed the strange behavior where the request for the
  channels on the right blocked other requests (just moved it out of the
link function, and into the controller.  The link function is only for
binding events and such to the DOM, afaik.
- new feature: current video playing is represented in the URL
  - links shared containing this parameter should function as expected
  - the parameter also serves as a "bookmark" of what video you left a
    channel on. pressing "back" should take you back the last video you
were watching on the previous channel.