adl-submit.py: use <base> in order to load remote resources in preview

public/adl-submit.py

@@ -356,7 +356,7 @@ def SubmitEvent(event, testOutputFile):
                 sys.exit(0)
             fp = open(testOutputFile, "w")
             s = contents.getvalue().decode()
-            s = re.sub(r'href="([A-Za-z0-9]*).css"', r'href="'+baseUrl+'\1.css"', s)
+            s = re.sub(r'<head.*>', r'\g<0><base href="%s">' % baseUrl, s, flags=re.IGNORECASE)
             fp.write(s)
             fp.close()