Meta-issue on remaining Transfuse issues

* [ ] Long HTML-documents getting cut off (reported?)
* [x] docx-files with document{0..n}.xml and not just document.xml are ignored https://github.com/TinoDidriksen/Transfuse/issues/14
* [x] spaces around -tags get removed https://github.com/TinoDidriksen/Transfuse/issues/16
* [x] email addresses inside `` get weird https://github.com/GrammarSoft/cg3/issues/79
* [x] nested runs which give invisible text https://github.com/TinoDidriksen/Transfuse/issues/19 – actually https://github.com/apertium/lttoolbox/issues/145
* [x] https://github.com/apertium/apertium/issues/217
* [x] https://github.com/TinoDidriksen/Transfuse/issues/28

Possibly also
- [x] CDATA is lost https://github.com/TinoDidriksen/Transfuse/issues/13
- [x] Google Docs docx files crash https://github.com/TinoDidriksen/Transfuse/issues/10