video.xsl doesn't output width or height for youtube videos

[Bellfalasch]

This makes responsive iframe not work.

The template:
<xsl:template name="stk:video.embed-youtube" as="element()">

I just added this to the template to make it work as a quick fix, and it's far from good (doesn't care about region-width).
<xsl:attribute name="width" select="$width"/>
<xsl:attribute name="height" select="$height"/>

Current template doesn't even output these values even though the JavaScript is looking for it when going for responsive iframes.