Lots of documentation cleanup
Docs updates
Fix problem with preview state storage in import listing

Fixes #877
fr-FR translation of the warning about saving settings only used on tiddlyspot-like servers
Docs updates
Include translated editions

@pmario and @bramchen and @xcazin

Maybe the titles of these tiddlers should be translated into their
respective languages? And possibly the text too?
Merge pull request #878 from xcazin/fr-FR

fr-FR translation of the warning about saving settings only used on tidd...