Change all WP.org references to use SSL

With WP.org now running full SSL, this pull request changes all http links to https links.

While this does not negatively impact links to things like the Codex article, for example, because there is a 301 soon to be a 302 permanent redirect, the unit testing suite, which relies on wget to grab a tarball of WordPress, *must* be updated for it to work after they turn http off and force https.

Link: https://make.wordpress.org/meta/2014/09/23/wordpress-org-is-now-forced-ssl/