git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@19436 b2dd03c8-39d4-4d8f-98ff-823fe69b080e
import JSON library. git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@12428 b2dd03c8-39d4-4d8f-98ff-823fe69b080e