Create `ExampleHelper` that use instead of `shared_context_examples.rb`
Create Scenario::Base that instead of module Scenario
Fix Scenario#validation to Scenario#valid?
Remove module TurnipFormatter::Scenario
Support Ruby 2.1.2
Merge pull request #39 from gongo/refactoring_scenario

Refactoring scenario
Remove shared_context Part.1
Remove shared_context Part.2
Remove shared_context !! Wow!!!
Oops forgot require.
Merge pull request #40 from gongo/remove_shared_context_specs

Remove shared context specs
Remove unuse method `TurnipFormatter::Step#attention?`
New mechanism of step template registration
Fix step classes (Big diff...)
Merge pull request #41 from gongo/refactoring_step

Refactoring step
Refactoring step_templates_for() using Enumerable#reduce
Remove caching of step_templates_for()

will introduced when the execution speed felt slow.
Rename javascript and stylesheet setter method.
Import step template stylesheets
Call Scenario#validation in initialize()