I18n and L10n

Closes #30 

This could be it: `angular-translate` is looking good.

All pieces are in place to support English and German. We want to add French at least. Italian, Croation - but we have to need for outside help. Once we have a richer dictionary of strings to translate, we could try perseids-dev to ask for collaborateurs.

`unusedTokenHighlighter` shows how to use the `translate` directive, navbar buttons and the searchCtrl the `translate` filter.

What do you think? Shall we go with this?



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__Update__

cae2091 hides this from the public - the reasoning behind can be found in the comments to `arethusa.js` inside this comment.

From now on we want to use translation tables for all future strings. Everything that's already inside of the applicatoin needs to be changed - we'll do this step by step and start to translate the application to German in the process. Once we've done with that, we activate the plugin again and let the users play with it.