Removed padding that caused black borders for vimeo videos.

When embedding vimeo media, the additional padding causes a black border to appear at the top/bottom of the video. Tested by using the iframe below in a video post.

```
<iframe src="//player.vimeo.com/video/22439234" width="500" height="281" frameborder="0" webkitallowfullscreen mozallowfullscreen allowfullscreen></iframe>
```