global function AddFactionXP

void function AddFactionXP( entity player, int amount )
{
	string faction = GetFactionChoice( player )
	// increment xp
	player.SetPersistentVar( "factionXP[" + faction + "]", min( FactionGetXP( player, faction ) + amount, FactionGetMaxXP( faction ) ) )
	
	// note: no notif for faction level up
}