WYSIWYG blocking has been removed on Brightcove media submodule

When the Brightcove media module was a separated project, the formatter for videos had a validation that prevents WYSIWYG modules like media_wysiwyg to render videos (iframe tags) straight to the WYSIWYG editor, however by some reason this was removed in 7.x-6 version. Here is a patch that includes it back for videos.

Note that this removal could be intended when this project was included into Brightcove module, however I can't figure out what could be the reason for this, so any review / comment / specification is welcome regarding this.

Also,this patch may not work correctly if this patch https://www.drupal.org/node/2540970#comment-12213640 → is not applied, this could happen because when media module looks for a correct way to render the video, it won't find the iframe formatter as the compatible way to render the video due to this patch, so it will use the video preview formatter, but this one is not working correctly, as this is looking for a default image rather than retrieving the thumbnail from brightcove. This is a minor issue if you use the Default renderer as this will only get noticed in the WYSIWYG editor, as video when viewed inside the entity will render correctly.