This lets us separate things like project news from other OSS and from
commercial postings, for example, allowing for people to subscribe to
different feeds with just the parts they are interested in.
Once a twitter account has been registered (using the twitter_register
management command), the twitter_post command wills start posting all
new news to twitter, once they are approved. It will only post news from
the past 7 days to avoid accidentally flooding with old news.
Since this can be used to bypass moderator approval and move items
to the frontpage of the site, they're blocked. We still allow the user
to make corrections in the text and other such fields.
"submitter", thus making it possible for a single person to manage
multiple organisations, as well as for a single organisation to have
multiple different manages.
Re-hook events and news items to use organisation of the submitter
instead of the user who did the submission. (product listings already
did this)
