polygon-edit: model.js -> models/polygon.js & add unit test
polygon-edit: delete DotList
polygon-edit: LineList.prototype.create -> LineFactory.get
polygon-edit: remove test code
polygon-edit: remove container param in Polygon class
polygon-edit: fix remove polygon bug
polygon-edit: convert line.js & dot.js to CoffeeScript
polygon-edit: fix some bugs
polygon-edit: convert polygon.js -> polygon.coffee
polygon-edit: fix line drawing on mode change
polygon-edit: migrate test codes to CoffeeScript
polygon-edit: add grunt-coffeelint
polygon-edit: add some tests for polygon and refactor Polygon class