Take stock of and implement missing Sphere APIs

[fatcerberus]

Oozaru doesn't currently implement the full Sphere v2 API. It implements enough to run the lion's share of code in the wild (which is pretty much just mine, but...), but it needs the full complement of APIs before it can integrated into the Sphere toolchain proper.

While this is being done, we also need to check whether more APIs need to be disabled before the API freeze for level 4 happens. This way API 4 can be the baseline target in order to run in both engines.