Add host.io API

Host.io is an API to get domains data - IP Addresses, DNS Records, Backlinks. Signup makes you eligible to for 1K free requests.

README.md

@@ -260,6 +260,7 @@ API | Description | Auth | HTTPS | CORS |
 | [GitHub](https://developer.github.com/v3/) | Make use of GitHub repositories, code and user info programmatically | `OAuth` | Yes | Yes |
 | [Gitlab](https://docs.gitlab.com/ee/api/) | Automate GitLab interaction programmatically | `OAuth` | Yes | Unknown |
 | [Gitter](https://github.com/gitterHQ/docs) | Chat for GitHub | `OAuth` | Yes | Unknown |
+| [Host.io](https://host.io) | Domains Data API for Developers | `apiKey` | Yes | Yes |
 | [HTTP2.Pro](https://http2.pro/doc/api) | Test endpoints for client and server HTTP/2 protocol support | No | Yes | Unknown |
 | [IBM Text to Speech](https://console.bluemix.net/docs/services/text-to-speech/getting-started.html) | Convert text to speech | `apiKey` | Yes | Yes |
 | [import.io](http://api.docs.import.io/) | Retrieve structured data from a website or RSS feed | `apiKey` | Yes | Unknown |