added tag for supporting apps prior to Chrome M39

updates tag to follow standard styleguide

Re-add disconnect_contacts in AccountDeleter

Update thor, coveralls and simplecov

Remove avatar, name, timestamp and interactions from publisher preview

Reset stuck exports and handle errors

It looks like all commands we use in production fixed the warnings
(rails 5.1), so we can update that again.

This doesn't add any value in the post preview:
* Avatar is already at the left-hand side of the publisher
* Timestamp is always "less than a minute ago"
* Interactions are disabled in the preview anyway

We don't display these things in the comment preview either, they only
need space and don't add any value to the preview.

Otherwise the export stays soft-locked and the podmin needs to reset it
manually.

Fixes #6225

Add missing indexes from #7234

Update gems

See #7234

Also remove `disconnect_contacts` methods, because contacts are already
removed with aspects memberships in `before_destroy`.

Render mentions in comment previews correctly

Disable rendering logging in production