Adds language links to footer

- Fixes #289 - Adds language links to the footer, primarily for the
inside pages so that English doesn’t need to be hunted down inside the
Google Translate Widget.
- Adds test for footer language links
- Moves GoogleTranslator to application_controller so it runs on all
routes.
- Merges CurrentLanguage module into GoogleTranslator module.
- Moves languages view partial to `/shared/` directory from
`/component/search/` directory.