Fix fullscreen video issue on Chrome/IE

Example of this bug in action: 

![](http://i.imgur.com/j1XS32E.png)

Also, Summernote seems to only add the `allowfullscreen` tag to Vimeo, and Youku embeds -- and they don't seem to have any configuration to change it. We may want to amend the `review_helper.rb` file to force-add it?