XLINK should use target=_blank

[GoogleCodeExporter]

What steps will reproduce the problem?
1. draw a box
2. enter an URL for that object
3. SAVE

What is the expected output? What do you see instead?

if one clicks on that URL the new object is shown inside the frame of the 
existing one. I would prefer it goes to target=_blank

Original issue reported on code.google.com by [email protected] on 5 Feb 2015 at 5:11