Fall back translations in unplugged pages
- Add helper for returning nil rather than error message on missing translations
Use more generic, raise/rescue `try_t` helper
Merge pull request #1043 from code-dot-org/fix_missing_unplugged_localization

Fall back translations in unplugged pages
Merge pull request #1044 from code-dot-org/finished

Deploy to delivered
Merge pull request #1046 from code-dot-org/delivered

Delivered into master