before this cell might be a good time to have a few setnences of text on what vo.conesearch *is* ?  Right now, there's very little of that, so it's hard for someone who isn't terribly familiar with VO to understand.  This would also be a good place to link to the docs (use links like ``http://docs.astropy.org/en/stable/vo/conesearch.html``, as that should auto-update as we release new versions).