support href (not just xlink:href)

Steps to reproduce:

• open Inkscape
• open attached SVG (below)
• it should display a square with dark-blue stroke and light-blue fill

What happened?

• the clone is not visible

What should have happened?

• I have tested opening the attached SVG in 4 browsers -> Opera, Chrome, Firefox & IE11. All display both square.

Inkscape Version and Operating System:

• Inkscape Version: 0.92.4 (5da689c313, 2019-01-14) on Windows 7 64 bit

<?xml version="1.0" encoding="UTF-8" standalone="no"?>
<svg
		xmlns:dc="http://purl.org/dc/elements/1.1/"
		xmlns:cc="http://creativecommons.org/ns#"
		xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#"
		xmlns:svg="http://www.w3.org/2000/svg"
		xmlns="http://www.w3.org/2000/svg"
		version="1.1"
		viewBox="0 0 30 30" >
		<rect	
				style="fill-opacity:1;stroke-width:1;stroke-opacity:1;fill:#92d9fc;stroke:#385d8a;"
				id="demo"
				width="10"
				height="10"
				x="0"
				y="0" />
	<use href="#demo" x="10" y="10" />
</svg>