Android: Preference syncing

[samuelclay]

Note that this only applies to preference syncing between iOS and Android clients and NOT with the web. People have different web preferences, so we should respect that. However, I would like all iOS and Android clients (phone and tablet) to use the same preferences with an option to turn off preference syncing.

On iOS we can do this with iCloud, so we don't need to involve the server. Is there an Android/Play equivalent?