core: Add state_machine gem
Rails 4.1.x: Patch for state_machine 1.2.0
core: Define state on order
core: Move order validations to checkout module
Move order flow logics to checkout module
rubocop: Add rules to ignore harmless codes
rspec: Fix to work the test for orders controller

And fix a bug at confirm action.
frontend: Fix to add missing detail of address
rpsec: Fix to work the test for views
rspec: Fix to work the test for cart
Rails 3.x: Fix to work the test

- update => update_attributes
- :customer => Comable::Customer.table_name.singularize.foreign_key
core: Add a spec for checkout

And fix the complete method to call without any arguments
fonrned: Remove no longer needed the codes
Merge pull request #50 from hyoshida/install-state_machine-gem

Install state machine gem