ENH: Support Nihon Kohden EEG-1200A V01.00

[larsoner]

Closes #8385
Closes #9462

Can at least read the data from #8385 (comment) with:

<string>:1: RuntimeWarning: Omitted 1 annotation(s) that were outside data range.

but looking at the annot, it appears to be at 7 sec and the data are only 1 sec long so this seems okay. Leaving as draft until I look more into some data that were shared privately.

@jacobshaw42 do you have any short snippets with annotations you could share (or record+share), ideally with also-exported EDF? Then we could add these to the test data and probably get things working quickly. (To answer your question from #9462 (comment), we can't use code you wrote if you've gotten inspiration from reading GPL code.)

Todo:

• Work on "sub-log" code, or at least warn that we don't support it
• Check that annotations read correctly
• Add some test files (ideally)

[larsoner]

@jacobshaw42 can you see if the annotations are correct for your file(s)? Or is there some timing issue?

Not sure how to read the sub-log stuff... might need to look into the file format spec for that. In the meantime maybe we should just emit a warning about not reading it, and get this in.