Missing bCs on bold

On style\Font.php:
```$xmlWriter->writeElementIf($style->isBold(), 'w:b');```
And should be:
```
$xmlWriter->writeElementIf($style->isBold(), 'w:b');
$xmlWriter->writeElementIf($style->isBold(), 'w:bCs');
```
Just like the italic one:
```
$xmlWriter->writeElementIf($style->isItalic(), 'w:i');
$xmlWriter->writeElementIf($style->isItalic(), 'w:iCs');
```