allow content to fallback to snippet

[cognition9144]

Some feeds only have summary but no content. However, according to the RSS 2.0 spec, it's totally valid. Fluent Reader should better the situation by falling back to snippet if no content

[yang991178]

The snippet field in the RSSItem object is simply the HTML text from content with tags stripped. Maybe you should take a look at the constructor of RSSItem to get the summary field from parsed feeds.

[cognition9144]

Well, it's a bit tricky. rss-parser doesn't seem to parse the summary field of atom feeds. So I may need to send a PR there first.

[yang991178]

Well, it's a bit tricky. rss-parser doesn't seem to parse the summary field of atom feeds. So I may need to send a PR there first.

I remember you can declare additional property you want when initializing the parser. Maybe you can also switch the npm dependency to the original rss-parser package since we don't actually need any functionality from the custom one anymore.