uglified formatter
use oj instead of json
Merge branch 'master' into nakano-teacher-mad

Conflicts:
	lib/rack/camel_snake.rb
reverted module overriding
use refinements
use JSON for tests
divide Oj::Formatter from Rack::CamelSnake
rubocop fix
only 2.1.0 version of ruby is available because of refinements
use refinements
rubocop fix
use block and delete tests for formatter
added tests for camelize and snakify
fix comments
delegate Formatter instead of inherit it
Merge pull request #4 from junsumida/nakano-teacher-mad

formatterのリファクタリング