Bugfix: Avoid IndexError when no video description is present

This plugin stopped working a few weeks ago on my machine (unable to view 'All Shows').  After some investigation, I noticed that an `IndexError` was being raised from `listShows()`.  This occurs due to the fact that the Vice: Shows page has a show listed without a description:
```html
<li class="story story-square">
    <a class="story_thumbnail" href="/every-woman"><img width="220" height="220" src="http://assets.vice.com/content-images/series/every-woman/show_image/showtrailer_vice_220x220.jpg" /></a>    <h2><a href="/every-woman">Every Woman</a></h2>
    <p></p>
</li>
```

When the regex encounters the empty `<p>` tag, it returns an empty string as the match.  When the following line attempts to get the `0` index of that empty string, an `IndexError` occurs.  

These changes return a `list` object with an empty string at the `0` index when no match is found by regex, thus avoiding the `IndexError`.

This bug could theoretically occur anywhere where the results of a regex are accessed at index `0` without first scrutinizing the results.

_ps: I love this plugin! Thanks for putting it up in the first place! (:thumbsup:)_