Do not reset direction

Please merge this. It fixed issue #3539. It doesn't hurt anything and it will only improve bi-directionality support. It allows the embedding of elements with `dir="rtl"` attribute value to render in their proper declared direction. Without this merge a workaround is needed:
```
[dir="ltr"] * { direction: ltr; }
[dir="rtl"] * { direction: rtl; }
[dir="ltr"] { direction: ltr; }
[dir="rtl"] { direction: rtl; }
```