Fix Bug in itex Extension

Firefox was too lenient, in allowing
you to append nodes from another document to
the svg canvas. Use adoptNode(), to do things
right. (Google Chrome is more strict about this.)

public/svg-edit/editor/extensions/ext-itex.js

@@ -75,7 +75,7 @@ $(function() {
 				$.post(ajaxEndpoint, {'tex': tex, 'display': 'inline'}, function(data){
 				    var children = data.documentElement.childNodes;
 				    while (children.length > 0) {
-				      mrow.appendChild(children[0]);
+				      mrow.appendChild(svgdoc.adoptNode(children[0], true));
 				    }
 				    S.sanitizeSvg(math);
 				    S.call("changed", [elt]);