Feature request: EPUB3 Support

[lgsl]

TM has the ability to export to epub, however when it does, it exports to EPUB version 2. Modern readers all support version 3, and several retailers also suggest the use of version 3 over 2.

EPUB3 has several advantages over EPUB2. For instance: footnotes and endnotes are handled in a more sensitive way. There are tags that can be used to mark those words in the text that are in other languages, and TTS devices can detect and so on.

It would be good to be able to export to v3 instead of 2, or as LibreOffie does: let the use choose between the version he/she needs.

[SuperTech]

Thank you for the suggestion. I have forwarded this improvement suggestion.