Fetch Gravatars over HTTPS.

No version number change necessary as the preceeding ones have not been
deployed yet either.
Fix UserVoice path problem.

Introduced in 035643f5a5958e4731ea5f68938f3bae2b9c38e7
Fix UNIX install instructions other than en.

Matching changes with 6070b19ecd563399ce8856ed21d90e6899519aa8