Included tools to help test webhooks, closes woocommerce#107

Author: claudiosanches

source/includes/wp-api-v2/_introduction.md

@@ -266,3 +266,5 @@ Some useful tools you can use to access the API include:
 - [Paw HTTP Client](https://itunes.apple.com/us/app/paw-http-client/id584653203?mt=12) - Another HTTP client for Mac OS X.
 - [RESTClient, a debugger for RESTful web services](https://addons.mozilla.org/en-US/firefox/addon/restclient/) - Free Firefox add-on.
 - [Advanced REST client](https://chrome.google.com/webstore/detail/advanced-rest-client/hgmloofddffdnphfgcellkdfbfbjeloo) - Free Google Chrome extension.
+- [RequestBin](https://requestb.in) - Allows you test webhooks.
+- [Hookbin](https://hookbin.com/) - Another tool to test webhooks.