Bug 845355: Replace show_toc field with a toc_depth field with more options.
Bug 845355: Clean up unit tests for new toc_depth field.
Bug 845355: Migration to remove show_toc field.
Start unit-testing the new TOC filter.
Fix bug 845355: Add depth to table of contents.
Clean up some test failures from toc_depth changes.
Add the template change to support the full range of toc_depth.
Clean up toc_depth migrations.