Clean up content modules header docs
Document the special horror player
Add an atomic command for overriding faction tactic
Add a server command to change faction's tactic
Add a human command to cycle tactic
Pick a new AI leader every turn even if others move

Individual actors may be unable to move due to, e.g., equipment.
Also, others may be able to move, but not shoot.
Also, now this depends on tactic.
At tactic change, clear all targets except the leader's
Break content API by inserting a player tactics field

I lied when I said we are already at 0.5.0.0 content API.
OTOH, only the ModeKindPlayer content is affected.
Leader now has all skills (unless actor handicapped)
Merge fisAI and fhasLeader
Rename fhasLeader to fleaderMode
Document (weakly) the tactic change command