Simplify .content width/margins.

Reduce magic numbers by switching fixed width to a margin elsewhere.
This has the added bonus of making the 'middle-width' .content
have a pleasing right margin.
Tidy up use of main width a bit.
Remove cached photos if hidden in admin interface.

Use the internal hash URL of the photo so that it can still be seen in
the admin interface.
Copy of main privacy file to work on.
[FixMindelo] Translation of the privacy page.

Omitted the credits and links to further information.
Merge branch 'fixmindelo-privacy'
Add OpenGraph meta elements (for #613).
Actually include the image, doh.
Merge remote-tracking branch 'upstream/master'
Merge branch 'master' into baiki