message: making prepack remove lib before building
diff: "scripts": {
  "docs": "typedoc --ignoreCompilerErrors --tsconfig ./tsconfig.json src",
  "karma": "karma start",
  - "prepack": "npm run build",
  + "prepack": "rm -r lib ; npm run build",
  "build": "tsc",
  "test": "mocha -r ts-node/register -r jsdom-global/register \"./test/**/*.{ts,tsx}\""
  },
  