Implement edit/save tasks for News

This implements edit/save tasks similar to how we've done it for the tracker app.  The content editor is the MarkItUp editor, allowing users to input their content Markdown style.  The database has been altered to store both the raw and markdown-parsed text which is parsed via GitHub's API (using the non-GFM option).

Still need to sort out the add task and probably should implement an authentication system (just using the tracker's GitHub mechanism should suffice, but I'd drop the usergroup code for this demo).