Use ESLint for checking for code style

package.json

@@ -9,7 +9,8 @@
   ],
   "scripts": {
     "precommit": "lint-staged",
-    "test": "npm run build && ava",
+    "lint": "eslint lib/* bin/*",
+    "test": "npm run build && npm run lint && ava",
     "prepublish": "npm run build",
     "build": "./build.sh",
     "pack": "pkg bin/now.js --config package.json --out-dir packed -t node7-alpine-x64,node7-linux-x64,node7-macos-x64,node7-win-x64"
@@ -29,8 +30,24 @@
       "test/*.js"
     ]
   },
+  "eslintConfig": {
+    "parserOptions": {
+      "ecmaVersion": 8
+    },
+    "extends": "eslint:recommended",
+    "env": {
+      "node": true,
+      "es6": true
+    },
+    "rules": {
+      "no-console": 0,
+      "no-empty": 0,
+      "no-control-regex": 0
+    }
+  },
   "lint-staged": {
     "*.js": [
+      "npm run lint",
       "prettier --single-quote --write",
       "git add"
     ]
@@ -82,6 +99,7 @@
   "devDependencies": {
     "alpha-sort": "2.0.0",
     "ava": "0.18.2",
+    "eslint": "3.18.0",
     "husky": "0.13.3-0",
     "lint-staged": "3.4.0",
     "pkg": "3.0.0-beta.29"