Typings support (#737)

* Updated scripts

* Updated .gitignore

* Removed symbols

* Fixed typo

* Added typings

* Updated test

* Added typings test

test/types/index.ts

@@ -0,0 +1,29 @@
+'use strict'
+
+import { Client, ApiResponse } from '../../index'
+
+const client = new Client({ node: 'http://localhost:9200' })
+
+// Callbacks
+client.info((err: Error | null, result: ApiResponse) => {})
+
+client.index({
+  index: 'test',
+  type: 'test',
+  id: 'test',
+  body: { hello: 'world' }
+}, (err: Error | null, result: ApiResponse) => {})
+
+// Promises
+client.info()
+  .then((result: ApiResponse) => {})
+  .catch((err: Error) => {})
+
+client.index({
+  index: 'test',
+  type: 'test',
+  id: 'test',
+  body: { hello: 'world' }
+})
+  .then((result: ApiResponse) => {})
+  .catch((err: Error) => {})