Removing unneeded css from head

[jenssss]

In the new version of reveal.js (4.0), the css for print pdf which is included from

org-reveal/ox-reveal.el

Lines 652 to 666 in 499c577

	;; print-pdf
	(if in-single-file ""
	(format "
	<!-- If the query includes 'print-pdf', include the PDF print sheet -->
	<script>
	if( window.location.search.match( /print-pdf/gi ) ) {
	var link = document.createElement( 'link' );
	link.rel = 'stylesheet';
	link.type = 'text/css';
	link.href = '%scss/print/pdf.css';
	document.getElementsByTagName( 'head' )[0].appendChild( link );
	}
	</script>
	"
	root-path)))))

seems to no longer be necessary. See the reveal docs at https://revealjs.com/upgrading/#remove-print-css-from-%3Chead%3E. Would it be possible to remove it, or maybe add an option to not include it in exports for people using newer reveal.js?

[yjwen]

Done. Removed for reveal.js 4