refactor: Merge typings into 11.4-dev branch

package.json

@@ -10,6 +10,7 @@
     "docs:test": "docgen --source src --custom docs/index.yml",
     "lint": "eslint src",
     "lint:fix": "eslint --fix src",
+    "lint:typings": "tslint index.d.ts discord.js-test.ts",
     "webpack": "parallel-webpack"
   },
   "repository": {
@@ -52,6 +53,9 @@
     "discord.js-docgen": "discordjs/docgen",
     "eslint": "^4.18.0",
     "parallel-webpack": "^2.2.0",
+    "tslint": "^3.15.1",
+    "tslint-config-typings": "^0.2.4",
+    "typescript": "^3.0.1",
     "uglifyjs-webpack-plugin": "^1.2.0",
     "webpack": "^3.11.0"
   },