refactoring

- mv klass.js
  - add klass/constructors.js, move to separate file
  - add klass/utils.js, move to separate file
- mv compiler.js
  - add compiler/scope.js, move to separate file
  - add compiler/marker.js, move to separete file
  - add compiler/node.js, move to separate file
  - add compiler/lexer.js, move to separate file
  - fix compiler/marker
  - remove parser#peek
- build v0.0.19