RSS Feeds - Have an option to show all new items, instead of just the latest new item.

[Paul Vincent]

Currently, the feed feature works as follows:

1. Download the contents of the RSS feed.
2. Sort the feed by "published date"
3. Looking at the last time there was new content, remove all entries equal to or older than this date.
4. Do we have any entries left in the feed?
   4.1. Yes: Take the latest one, and send it to the channel in the format specified.
5. Wait X seconds (30 s by default) and return to step 1.

We can add an option to step 4 that just says: "Write all new entries to the channel". This way, if a hot topic is happening on Twitter or elsewhere, we can catch all the news as it happens in the chat room.