message: Make lib dir prior to building
  p option will not error if lib already exists
diff: "scripts": {
  "reskindex": "node scripts/reskindex.js -h header",
  "reskindex:watch": "node scripts/reskindex.js -h header -w",
  - "build": "npm run emoji-data-strip && npm run reskindex && babel src -d lib --source-maps",
  - "build:watch": "npm run emoji-data-strip && babel src -w -d lib --source-maps",
  + "build:init": "mkdir -p lib && npm run emoji-data-strip",
  + "build": "npm run build:init && npm run reskindex && babel src -d lib --source-maps",
  + "build:watch": "npm run build:init && babel src -w -d lib --source-maps",
  "emoji-data-strip": "node scripts/emoji-data-strip.js",
  "start": "parallelshell \"npm run build:watch\" \"npm run reskindex:watch\"",
  "lint": "eslint src/",
  