Internationalization and locale improvements

[ripperdoc]

Currently, a publisher can be set to Swedish and English, but the choice is implicit and made in a complicated algorithm internally. Often, it ends up being English (due to browser settings?). It's not visible in the URL as recommended by Google. Here's proposed actions:

• [ ] Create a good debug message that explains exactly why a specific locale is chosen. Write this out somewhere hidden on the page, and make it easy to test all variants of locale input (from URL, from browser, from session, from user setting).
• [ ] Enable internationalized URLs, so /en/ or /sv/ is prefixed. A publisher can have a default language, in those cases, the url without prefix is the default language (check SEO implications).
• [ ] Tag articles by language

This is very tricky to get right, so further study needed.

[ripperdoc]

I think I got it right! And closing.