Remove es3 syntax check which causes us more problems than money

Author: Uku Pattak

package.json

@@ -29,7 +29,7 @@
     "build:commonjs": "babel src --out-dir lib",
     "build:umd": "cross-env NODE_ENV=development webpack src/sqlFormatter.js dist/sql-formatter.js",
     "build:umd:min": "cross-env NODE_ENV=production webpack src/sqlFormatter.js dist/sql-formatter.min.js",
-    "prepublish": "npm run clean && npm run check && npm run build && check-es3-syntax lib/ dist/ --kill --print"
+    "prepublish": "npm run clean && npm run check && npm run build"
   },
   "repository": {
     "type": "git",
@@ -52,7 +52,6 @@
     "babel-plugin-transform-object-rest-spread": "^6.8.0",
     "babel-plugin-transform-runtime": "^6.8.0",
     "babel-preset-es2015": "^6.14.0",
-    "check-es3-syntax-cli": "^0.1.1",
     "cross-env": "^1.0.7",
     "eslint": "^3.1.1",
     "jasmine-core": "^2.4.1",