Change from "Copyright" to "Rights" per w3c/whatwg metatag guidelines

Looks reasonable to me. Are you working on a patch to fix this Göran? If so then the assigned field is right. If not then you should unassign yourself.

Unassigning as it seems like Göran is not working on this.

This patch replaces the meta tag, updates the README.txt, and adds an update script to replace update existing records.

It just needed a reroll.

This is related to #2267501: Replace twitter:image with twitter:image:src in that both of them are renaming existing meta tags.

I've realized we have an API problem - any sites that exported their meta tag configurations, either through Features, Context, Panels or Views, will not be caught by the update script, and there's nothing in the API to make it use the old values until the configurations are resaved. I've added #2298337: Add structure in API for meta tags to replace others to handle this.

Needs improvements per #2267501: Replace twitter:image with twitter:image:src.

Updated to match the twitter:image patch.

I forgot part of the patch. Per the twitter:image tag change, this will still support sites that have the old value, those will be transparently displayed as the new meta tag until their configuration is updated.

Committed.