v2.0.2

Bug fixes

• Null values persisted to translation_values.value when an editor cleared a field.
  Clearing a locale value in the Keys or Groups form could send null to the repository,
  which was stored as-is in the database instead of an empty string.
  Both TranslationRepository and TranslationGroupRepository now normalise any null
  field value to '' before persisting.

Documentation

• Added Editorial interface section to the README covering the Keys and Groups edit
  forms (fields, read-only behaviour, auto-sync on save), the allow_empty checkbox and
  its effect on validation in each module, and the null-to-empty-string normalisation rule.