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.
Merge pull request #12 from bcipolli/1624

1624
Didn't know ben wanted centered text!
Merge branch '1624' of https://github.com/dylanjbarth/ka-lite into 1624
Merge pull request #1629 from dylanjbarth/1624

Fix for #1624