Add i18n and L10n

[meshy]

We get a lot of international traffic. (Especially from Russia! Привет!) It would be nice to reward that with i18n support.

[mkoistinen]

See also #75. I recommend add support for Transifex, crowd source translations. Note, this will also affect permalink, so we may need to also build in some custom middleware to redirect 'language-less' (old links) references to the new-style urls.