See if we can avoid genealogy in lesson permalinks

[jeremyboggs]

WP automatically creates permalinks based on a post's genealogy if a post has ancestors (e.g. has a parent post). This breaks existing links in our lessons, so we should look to see if its possible to build permalinks for lessons that only include the lesson's slug and not any of its ancestors' slugs.

[jeremyboggs]

Easiest way to do this would be to remove the "hierarchical" feature from the Lessons post type. Could also just remove any parent relationships in individual lessons.