Make civilian militants and saboteurs part of civilian garrison.

[billw2012]

Instead of being standard units, they should be part of the civilian garrison of a town, and behavior should be controlled by our AI system. This has these benefits:

• recruiting them to your squad is permanent (they don't disappear)
• you can use them to capture the town properly
• their stolen loadouts are saved
• they spawn/despawn correctly instead of starting new each time
• the militant and saboteur missions can be converted into actions/goals