addNpcRelationship(Type, Actor1, Actor2, ..., ActorN)


USE:
Add (or change if a relationship already exists) a relationship between 2 or more NPCs. The list for 'Type' is:
- Dating (2 actors only)
- Spouses (2 actors only)
- Siblings
- ParentChild (2 actors only, parent is Actor1, child is Actor2)
- Cousins
- BossEmployee (2 actors only, Boss is Actor1, employee is Actor2)
- Colleagues

TYPE: Command, non-Ref
RETURNS: /
THEME: NPC-NPC
COMPARE: removeNPCRelationship, hasRelationship

EXAMPLE:
    addNpcRelationship(Dating, John, Maria)
    "John and Maria have started dating. What a matchmaker I was!"
    "A few months later ..."
    addNPCRelationship(Spouses, John, Maria) // The 'dating' relationship will be upgraded to spouses
    
    Jack:: "Have you met my brother, Jason?"
    addNpcRelationship(Siblings, Jack, Jason)
    "A few days later ... in a seperate scene perhaps"
    Jack:: "Here's my sister, Natalie."
    addNPCRelationship(Siblings, Jack, Natalie)
    "The game will now also recognize Jason and Natalie as siblings."