add support for chapter level usfm filtering and remarks

[mshannon-sil]

This PR addresses issue #836 and is dependent on changes in machine.py that are in this PR: sillsdev/machine.py#285.

This passes the chapters argument into the update_usfm method from machine.py so that any usfm markers that are not the \id marker or in the requested chapters are omitted. It also updates remarks to be applied at a chapter level rather than at a book level.

A couple questions/notes:

• For books with a single chapter like Jude, are we okay always assuming that there will be a \c 1 marker, or is it possible projects may omit it? Because the way the remarks algorithm now works for a book like Jude, it creates a remark for chapter 1, but the remark won't be applied if there is no \c 1 marker.
• I didn't update the more manual version of updating usfm in the translate_usfm method, since the way silnlp is set up it doesn't get used when books/chapters are specified. Also, updating it to support chapters would include having to import more from machine.py, particularly filter_tokens_by_chapter that we didn't want to import if we didn't have to. If I should still add support for chapter level drafting to this manual version regardless, please let me know.

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This change is 

[Enkidu93]

Looks good!

I think we can assume that \c 1 always exists. I've never seen it omitted I don't think. And if it were omitted, I think it would cause other problems in our tools. Maybe you could ask the EITL team if they've seen this before if you'd like to double-check?

I'm fine with only updating translate_book, but that's more a question for Ben and Damien, I guess.

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Reviewable status: complete! all files reviewed, all discussions resolved (waiting on ddaspit).