[REFACTORING] Templates refactored.
[FEATURE] Application conventions has been changed.

It is expected by default that all application classes are namespaced
within GemName module. The module name is excluded from path.

All classes are additionally namespaced within submodules (Models, Services etc.).

== Changes

* models directory: gem_name excluded from the pathnames.
  app/models/gem_name/ -> app/models/
  spec/models/gem_name/ -> spec/models/
* namespace for the models: Models module added.
  GemName::Model -> GemName::Models::Model
  (table names remains the same)
* attributes directory: gem_name and models excluded from the pathnames.
  app/models/gem_name/attributes/ -> app/attributes/
* services directory: gem_name excluded from the pathnames.
  app/services/gem_name/ -> app/services/
  spec/services/gem_name/ -> spec/services/
* namespace for the services: Services module added.
  GemName::Service -> GemName::Services::Service
* type of the class added to translations:
  config/locales/model.(ru|en).yml -> config/locales/models/model/(ru|en).yml
  config/locales/service.(ru|en).yml -> config/locales/services/service/(ru|en).yml
[FEATURE] Core generator scaffolds config/initializers/i18n.rb settings.
[REFACTORING] Yard docs updated in Service and Model generators' template
[REFACTORING] Service template uses the #escape wrapper instead of #transaction.

Due to adding the #escape to 'hexx' core gem the usage of #transaction (ActiveRecord)
is not necessary any longer. It should be used only then database transaction needed,
not for the simple rescuing.
[FEATURE] Service generator's -d key.

It is possible to select adding common service YARD docs explicitly.
Then the option is selected, full docs will be added for Services class and the #subscribe method.

== Changes

* Hexx::Generators::Service - the new class option added.
* Service generator class template.
[FEATURE] Model generator's -u key.

The key allows adding 'has_uuids' callback from the 'uuids' gem to the model.

== Addons

* Hexx::Generators::Uuids - injects uuids to the model.
* Hexx::Generators::Model -u option.
* Hexx::Generators::BaseObject##from_template helper.
[FEATURE] Migration generator checks if a migration hasn't been added before.