Allow Invisible Marking of Word Division

[mhorspool]

In countries such as Thailand, word division is inferred, so they do not use spaces. They are consequently unable to dynamically reflow braille without words being split over a line break.
To account for these cases, I would like the EBraille standard to permit a second word division character in addition to a space, which is recognised by the reading agent as a word division character for the purposes of line wrap, but otherwise not displayed to the reader.
A potential possibility for this second character is the Zero Width Joiner, U+200D.

[bertfrees]

There is the wbr element that could potentially be used for this:

https://daisy.github.io/ebraille/best-practices/tagging/#example-text-optionally-broken-with-no-hyphen

[mattgarrish]

Interestingly, W3C is working on a document on supporting Thai formatting: Thai Script Resources

The section on word segmentation led to some notes by Richard Ishida where he suggests using Zero Width Space (U+200B) to separate words together with Word Joiner (U+2060) to prevent breaks between syllables.

wbr can be used in place of ZWSP, but WJ isn't accounted for -- but we also only recommend the characters to use, so it's not like it would be illegal to use others.