I18n/locale support

[eelcoj]

For the v1 release I want to, at the very least, make sure the logic is in place to built i18n-powered sites.

For a start I put up this PR #127

Besides some, typical Rails, set up (routes, default_locales), one can put content into locale-namespaces folder (eg. app/content/posts/de/*/*.*) and all should work.

Biggest unknown right now is how this works/should works with the build step.

[eelcoj]

While I have made good progress on i18n support, there are still quite a few tricky bits to solve. So I am removing this from the v1 release.

I have soon a project that needs good i18n support thus that will be good testing ground for it.