Generated the structural test references

[iherman]

The preview and diff files generated automatically are useless: the former does not include the vocabularies and the latter is way too large. A githack preview is preferable: this URL points to a typical occurence of a epubcheck test reference.

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Preview | Diff

[iherman]

Nitpicking: s/Epubcheck/EPUBCheck/ 😊

Oops... has been taken care of. Thx.

[mattgarrish]

Too big to verify it all, but seems to be working properly.