Tell search engines not to index */wikipedia-extract, plus some other bits that haven't been added to robots.txt.production. Add ISWCs to work meta description.
Merge remote-tracking branch 'bitbucket/robots-tweaks' into beta

* bitbucket/robots-tweaks:
  Tell search engines not to index */wikipedia-extract, plus some other bits that haven't been added to robots.txt.production. Add ISWCs to work meta description.