message: add start script
diff: "build": "npm run build-code && node ./node_modules/@bentley/build-tools/scripts/ignoreargs.js 1>&2",
  "lint": "tslint -p . 1>&2",
  "build-code": "tsc 1>&2",
  + "start": "node ./lib/ConvertToImageGraphics.js",
  "clean": "rimraf lib .rush package-deps.json ../../generated-docs",
  "test": "",
  "docs": "",
  