message: remove duplicate merge-stream dependency
diff: "@types/vinyl": "^1.1.29",
  "@types/vinyl-fs": "0.0.28",
  "dom5": "^2.0.1",
  - "merge-stream": "^1.0.1",
  "multipipe": "^1.0.2",
  "parse5": "^2.2.2",
  "plylog": "^0.4.0",
  "gulp-tslint": "^6.1.1",
  "gulp-typescript": "^2.13.4",
  "gulp-typings": "^2.0.0",
  - "merge-stream": "^1.0.0",
  + "merge-stream": "^1.0.1",
  "run-sequence": "^1.2.0",
  "sinon": "^1.17.6",
  "temp": "^0.8.3",
  