Merge branch '448-make-use-of-existing-translations' into 'master'

Make use of Existing Translations

Adds first translations to source code and sets up transifex config
file. Pull more translations later with:

```bash
 cd briar-android
 tx pull --mode=developer
```
Closes #448

![device-2016-06-23-145337](/uploads/14c557adf185dce516ca94295b4db965/device-2016-06-23-145337.png)

See merge request !226