Fix problem with static "all tiddlers" export
Revert to using fieldmangler for adding fields

In 5.1.5 we switched to using `<$action-setfield>` instead of
`<$fieldmangler>`. The problem was that in the process we lost the
validation of field names, making it possible to create fields with
illegal names

Fixes #1186
Typo in Greek translation
Sort languages by description instead of title
Added nl-NL translation from @gernert

Thank you @gernert

I’ve pushed a new prerelease, let me know if anything looks wrong.
Add recent translations to translators edition
Fix problem with tm-add-field for existing fields

Fixes #1197
Typos