Greek translation

First attempt for translating Greek (Greece)
Fixed the description of the operator

the previous description was erroneous: the operand is not the number of entries to return, but the position of the entry to select.
Corrections to el-GR translations

Some minor corrections to translations.
Add support for custom search result visualisations
Docs update

Fixes #1014 raised by @erwanm
First pass at an `--editions` command

Also added a “description” field for wiki folders.

Right now there’s too many editions listed. I think we should by
default only list editions whose `tiddlywiki.info` file has
`showInListings` set to `true`, and have an `--editions all` command
that lists everything.

@pmario please could you check that the editions in your
`TIDDLYWIKI_EDITION_PATH` are correctly listed?
Update cla-individual.md
Allow control over default search results tab
Merge pull request #1015 from erwanm/patch-3

Update cla-individual.md
Adding recursive sort parameter to toc macro
Merge pull request #1016 from Evolena/patch-1

Adding recursive sort parameter to toc macro
Merge pull request #1012 from erwanm/patch-1

Fixed the description of the operator
Update selectWidget example (the tag was deleted)
Merge pull request #1018 from Evolena/patch-2

Update selectWidget example (the tag was deleted)
Add zh caption of default search results
Add zh help text of editions command
Russian: Add support for custom search result visualisations
Add support for splitting standalone translations
Add Danish translation
Merge pull request #1020 from andrey013/ru-RU

Russian translation update