chore(package.json): add eslint and lint task

.eslintrc

@@ -0,0 +1,25 @@
+{
+  "parser": "babel-eslint",
+  "env": {
+    "browser": true,
+    "node": true,
+  },
+  "ecmaFeatures": {
+    "arrowFunctions": true,
+    "classes": true,
+    "modules": true,
+    "jsx": true
+  },
+  "rules": {
+    // Possible Errors
+    "comma-dangle": "always",
+    // Best Practices
+    "consistent-return": "never",
+    "yoda": "always",
+    // Variables
+    "no-use-before-define": "nofunc",
+    // Stylistic Issues
+    "camelcase": "never",
+    "no-underscore-dangle": "never",
+  },
+}

package.json

@@ -8,6 +8,7 @@
     "build": "rm -rf ./lib && babel --stage=1 ./src --out-dir ./lib",
     "build_client": "cd examples/gh-pages && npm i && npm run build_client",
     "dev": "cd examples/gh-pages && npm i && npm run dev",
+    "lint": "eslint src",
     "test": "jest"
   },
   "repository": {
@@ -49,6 +50,8 @@
   "devDependencies": {
     "babel": "^5.1.13",
     "babel-core": "^5.1.13",
+    "babel-eslint": "^3.1.7",
+    "eslint": "^0.21.2",
     "jest-cli": "^0.4.0",
     "tomchentw-npm-dev": "^1.2.0"
   },