Handle entries that have no HTML content.

Some sites, notably ABC News, provide just plain-text content or a
practically identical HTML summary, resulting in neither appearing on
the feed.  This checks the output of the HTML content extraction and
falls back to the summary if that comes up empty.

tornadonews/tornadonews.py

@@ -69,10 +69,15 @@ class FeedEntry(object):
         Parse the feedparser-generated entry dict and return a FeedEntry
         object from it.
         """
-        if 'content' in entry:
+        content = None
+
+        if entry.get('content'):
             html_content = filter(lambda c : 'html' in c['type'], entry['content'])
             content = ''.join([c['value'] for c in html_content])
-        else:
+
+        # If the content is empty or not present, then use summary.
+        # ABC news gives plain text (not HTML) content.
+        if not content:
             content = entry['summary']
 
         try: