Add i18n translations

[aendra-rininsland]

Given how little actual text there is in the app, it would be really easy to internationalise it using angular-translate. Am thinking Spanish, German, French, Japanese, Cantonese and Mandarin to start out with, in that order.

[aendra-rininsland]

Wanting to help with translating Axis?

It's easy! Fork this file and add your language's strings as the translation values (Make sure to keep all the "ALL CAPS" text intact — don't edit it!). Then either submit a PR (preferred) or post it as a Gist, linking to it via a comment on this issue.

Many thanks! The non-English-speaking data journalists of the world thank you!