fix(package.json): use flow-copy-source

package.json

@@ -10,16 +10,14 @@
     "flow": "flow",
     "flow:coverage": "for file in src/**.js test/**.js; do echo $file; flow coverage $file; done",
     "flow:watch": "flow-watch -e js,js.flow,flowconfig --ignore lib/ --ignore node_modules/ --watch .flowconfig --watch src/ --watch test/",
-    "gen-flow-files": "flow gen-flow-files src/ --out-dir lib",
-    "copy-flow-files": "cd src; copy *.js.flow **/*.js.flow ../lib",
-    "build": "rimraf lib && babel src --out-dir lib",
+    "build": "rimraf lib && babel src --out-dir lib && flow-copy-source -v src/ lib",
     "test": "NODE_ENV=production BABEL_ENV=test nyc --reporter=lcov --reporter=text mocha $npm_package_config_mocha",
     "test:watch": "mocha --watch $npm_package_config_mocha",
     "codecov": "nyc report --reporter=text-lcov > coverage.lcov; codecov",
     "commitmsg": "validate-commit-msg",
     "precommit": "npm run lint && flow",
     "prepush": "npm test",
-    "prepublish": "npm run lint && flow && npm test && npm run build && npm run copy-flow-files",
+    "prepublish": "npm run lint && flow && npm test && npm run build",
     "open:coverage": "open coverage/lcov-report/index.html",
     "semantic-release": "semantic-release pre && npm publish && semantic-release post"
   },
@@ -72,6 +70,7 @@
     "eslint-plugin-flowtype": "^2.30.0",
     "eslint-watch": "^3.0.0",
     "flow-bin": "^0.42.0",
+    "flow-copy-source": "^1.2.1",
     "flow-watch": "^1.1.0",
     "husky": "^0.13.1",
     "istanbul": "^0.4.5",