Adding in accouncements app.
Adding code to incorporate announcements.
Deleted showing announcement body; played with styling.
Moving announcements app into python-packages
Adding migrations, including app only for central server
Setting site_wide default to True, since nothing shows unless it's site-wide!
Mark HTML as safe, so that it comes through clean.
Didn't know ben wanted centered text!
Fix for #1638 : show localized node descriptions