message: Upgrade vega and vega-lite
diff: "eslint": "^3.17.1",
  "uglify-js": "^2.8.11",
  "watchify": "^3.9.0",
  - "vega": "^3.0.0-beta.25",
  - "vega-lite": "^2.0.0-alpha.4"
  + "vega": "^3.0.0-beta.27",
  + "vega-lite": "^2.0.0-alpha.7"
  },
  "dependencies": {
  "d3-selection": "^1.0.5",
  