crawler: improve html iter code

Ignores tags without attributes. Avoids bug with unclosed tags.

morss/crawler.py

@@ -368,7 +368,7 @@ class BrowserlyHeaderHandler(BaseHandler):
 def iter_html_tag(html_str, tag_name):
     " To avoid parsing whole pages when looking for a simple tag "
 
-    re_tag = r'<%s(\s*[^>])*>' % tag_name
+    re_tag = r'<%s\s+[^>]+>' % tag_name
     re_attr = r'(?P<key>[^=\s]+)=[\'"](?P<value>[^\'"]+)[\'"]'
 
     for tag_match in re.finditer(re_tag, html_str):