Cover remaining (incorrectly scheduled) calls

[R00tB33rMan]

This resolves #399 by properly delegating open and close operations on the correct entity scheduler. Let me know if any other changes are needed/requested!

[Jikoo]

I'm good with this, but the underlying problem is that the top inventory is backed by an item list which can be modified from the region of the owner and the region of any viewers. This just prevents the server from noticing that there is a problem because it doesn't know how our inventory's internals are handled.

I think the only way to get an actually safe short term fix would be to hack concurrency into the backing item list, but that's a lot more invasive than what OI currently does. I don't really want to be injecting replacement modified server classes, but I think with how locked down reflective access to final members is that would be the only possible course of action short of rewriting the inventory system to add an extra sync layer.