Adding default CSS for tei-xenodata (display:none)

Author: jamescummings

test/CETEIcean.css

@@ -906,6 +906,10 @@ tei-witdetail {
   display:none;
 }
 
+tei-xenodata {
+    display:none;
+}
+
 /* styles for HTML shell and HTML elements in TEI (e.g.,<a> and <img>) */
 html > body {
   margin: 0;