Adds missing spawn events for items

[Ryxias]

To be consistent with the @event Item#spawn event that is fired in Room#spawnItem

Addresses #73

[seanohue]

Code-wise it looks good to me, design-wise I have a question/scenario:

I don't think this would break anyone's code and it definitely makes sense to emit an event in those spots. But I wonder if someone would still be able to differentiate whether the item was spawning for the first time or being rehydrated or something? If not, I could see that causing bugs. Maybe the container it is spawned into could be passed as an argument? (the room, npc, item container, etc.)

[Ryxias]

That is a very good point @seanohue; this pattern could cause multiple spawn events to be emitted on any single creation attempt.

A workaround would be to detect if an item has been spawned already before emitting the event... but that seems kind of, inelegant. I'll think about it

[seanohue]

Maybe something like item.emit('spawn', room) or item.emit('spawn', item); so that one could check against where it is spawned. That said, such a change could always be made later in case there is something that breaks or is otherwise backwards-incompatible.

[seanohue]

Has this been tested in the wild yet?

[azigler]

I've tested this and I'm not encountering duplicate spawn events per item. All of these new events are emitted only during hydration, which only happens when:

• the server boots and initially spawns the item,
• an area updates and triggers a respawn of the item, or
• a player holding or equipping the item logs on

An item won't be spawned/hydrated in multiple places and the event won't be emitted multiple times per item, as each spawn/hydrate creates a unique item.

Separately, there's no way to differentiate between an item that's spawned for the first time and an item that was simply rehydrated. If a player possesses an item (either in their inventory or equipped) that later respawns back in its original area (thus creating a second copy of the item), a spawn event will fire when the player logs in and hydrates their inventory or equipment while they possess the original item, and a spawn event will fire at the time when the replacement item respawns at its original location. Those are two separate items, however, so each should trigger their own Item#spawn event.

These changes look good to me!

[seanohue]

Came across this again while going through open, public PRs that I'm mentioned in.
This looks ready to merge but unfortunately I don't have merge permissions at this point.

Hoping to draw attention to it with a comment.