message: build: add weex factory dev script
diff: "dev:ssr": "rollup -w -c build/config.js --environment TARGET:web-server-renderer",
  "dev:compiler": "rollup -w -c build/config.js --environment TARGET:web-compiler ",
  "dev:weex": "rollup -w -c build/config.js --environment TARGET:weex-framework",
  + "dev:weex:factory": "rollup -w -c build/config.js --environment TARGET:weex-factory",
  "dev:weex:compiler": "rollup -w -c build/config.js --environment TARGET:weex-compiler ",
  "build": "node build/build.js",
  "build:ssr": "npm run build -- web-runtime-cjs,web-server-renderer",
  