Add login functionality.
Add admin notice if the current theme doesn't add theme support for `message-board`.
Add trash link template tags.
Add topic spam template functions.
Add topic/reply edit template functions.
Thread positions.
First round, of many, dealing with post status changes.
Topic voices should be a single meta value in a comma-separated list. This will prevent things getting out of control with potentially 100s or 1,000s of voices.  That's a lot of meta values.
First pass at the post lists tables.