Add TABLE/THEAD/TBODY/TR as element to not consider blank

[LinFeng1997]

For Example：

<table>
    <thead>
        <tr>
            <th></th>
        </tr>
    </thead>
    <tbody>
        <tr>
            <td>content</td>
        </tr>
    </tbody>
</table>

will to be：

| content |

I hope this:

|  |
|--- |
| content |

[LinFeng1997]

solution:

function isBlank (node) {
  return (
    ['A','TABLE','THEAD','TBODY','TR','TH', 'TD', 'IFRAME', 'SCRIPT', 'AUDIO', 'VIDEO'].indexOf(node.nodeName) === -1 &&
    /^\s*$/i.test(node.textContent) &&
    !isVoid(node) &&
    !hasVoid(node)
  )
}

[jalbertbowden]

don't forget caption