Optimization:
  - save Localization record only when default_value is changed - ActiveRecord always save records(even when no changes are present) when one of columns is serialized
  - save nil values in redis cache
  - optimize deleting localizations - do not create localization only to immediately destroy it
  - fix saving default_value from options[:default] in lookup method - normalize keys first because options[:scope] should be applied too
Merge pull request #28 from Bonias/optimization

Optimization