code: function Renderer(game, width, height, tileSize, canvasClassName) {
          this.layers = [];
          this.game = game;
          this.canvas = document.createElement('canvas');
          this.ctx = this.canvas.getContext('2d');
          this.canvas.className = canvasClassName || 'renderer';
          this.buffer = this.canvas.cloneNode();
          this.bufferCtx = this.buffer.getContext('2d');
          this.tileSize = tileSize || this.tileSize;
          this.resize(width, height);
  
      }
docs: Renders the current game state using html5 canvas.
  @class Renderer
  @constructor
  @param {Game} game - Game instance this obj is attached to.
  @param {Number} width - Width of the map view in tiles.
  @param {Number} height - Height of the map view in tiles.
  @param {Number} tileSize - Width and height of tiles when drawn.
  @param {String} [canvasClassName='renderer'] - Css class name for the canvas element.