Consolidates translation code

Fixes #565 - consolidates translation code.
isTranslated edit

- Adds isTranslated check to show method, if the page wasn’t translated
and becomes translated.
- Simplifies isTranslated method.
Update Capybara settings and specs for translation
Nullify GOOGLE_TRANSLATE_API_TOKEN in tests

Nullify GOOGLE_TRANSLATE_API_TOKEN in tests so they don’t throw a VCR
error if it is set.
Merge pull request #593 from codeforamerica/565-remove-server-cookie

Consolidates translation code