Update importing so we don't open every imported tiddler

Instead we just display a report with links to each imported tiddler.
Should make importing much faster.
Ensure that $:/isEncrypted is reset if modified
Translation of recently added translateable strings.
Merge pull request #426 from xcazin/fr-FR

Translation of recently added translateable strings.
Use import report tiddler only if more than one tiddler is imported

If there’s only one, just display the tiddler itself.