Languages page is not i18nized

Hi @aronasorman,

Branch **Develop**

I have fixed the issue about the "not i18nized texts and buttons" at the page like:
* Show beta language packs checkbox text.
* Set as default buttons.
* Up to date texts.
* Languages Desciption texts.
* Delete buttons.
* Delete Subtitles button.
* Up to Date texts.

To reproduce:

    Login and set the language to non-english (example: French)
    Visit the languages page at http://127.0.0.1:8008/update/languages/
    Notice that the texts and buttons is still in English, see screenshot.
![27023714-848f-11e4-9d5a-7c33263c18da](https://cloud.githubusercontent.com/assets/2810009/5452000/e09d183a-8550-11e4-97ed-a3752eeb0e20.png)