SOFRIA export fails with verse straddling partial paragraph preceded by note.

[mvahowe]

Some USX, when rendered as SOFRIA, throws the following error:

TypeError: Cannot read property 'push' of undefined
    at e.exports.action (/home/mark/repos/proskomma-js/dist/index.js:121:56362)
    at e.exports.renderEvent (/home/mark/repos/proskomma-js/dist/index.js:8:115328)
    at e.exports.renderItem (/home/mark/repos/proskomma-js/dist/index.js:121:46054)
    at e.exports.renderContent (/home/mark/repos/proskomma-js/dist/index.js:121:44829)
    at e.exports.renderSequence (/home/mark/repos/proskomma-js/dist/index.js:121:44628)
    at e.exports.renderDocument1 (/home/mark/repos/proskomma-js/dist/index.js:121:42927)
    at e.exports.renderDocument (/home/mark/repos/proskomma-js/dist/index.js:8:114742)
    at Xa.sofria (/home/mark/repos/proskomma-js/dist/index.js:121:308821)
    at Object.sofria (/home/mark/repos/proskomma-js/dist/index.js:121:354468)
    at Xu (/home/mark/repos/proskomma-js/dist/index.js:121:258849)

I managed to replicate the error with some short USX fragments. The error seems to happen when a verse started in one paragraph ends halfway through another paragraph, and when the first paragraph also contains a note. (Both these conditions must be true to see the error.)

sofria_works_usx.txt
sofria_also_works_usx.txt
sofria_no_works_usx.txt
sofria_this_no_works_neither_usx.txt

[mvahowe]

The PERF endpoint works with all those test files, so the problem appears to be specific to SOFRIA export.

[mvahowe]

I made ProskommaRender errors more informative:

Error: Exception from action 'identity' for event startWrapper: Error: outputContentStack is empty before pushing to its first element

So it looks like a stack management thing.

[mvahowe]

My previously failing tests now pass. The issue was that I was clearing the chapter and verse state at the end of every sequence, when in fact this should only happen at the end of the main sequence.

[mvahowe]

Made a PR to proskomma-json-tools. Once that has been merged we'll refresh that module in Proskomma, which ought to fix the issue.