Luggage

- Luggage will now only try to grab items it can see and reach
- if Luggage gets stuck near an item, its reach will slowly increase until it can hopefully grab the item
- Luggage will try not to go back to its owner until all items in the area are collected
- whistling for Luggage or spawning it will give it a cooldown before it starts collecting items again

- whistling for Luggage will make it dismount its vehicle
- Luggage will not run away if its inventory is open
- attempting to swing at Luggage when attacking will now bypass it and will attack anything behind it. It basically acts like it isn't there.
- added new whistle command. Pressing this key (ALT + ` by default) will make luggage wait in place. Luggage that are waiting will emit sweat particles. Press the key again to let them freely move.

- added a step height to Luggage. It should now struggle less with climbing up hills. 

Please report any and all issues to the issue tracker, thank you!