(add client request)
https://mandrillapp.com/api/docs/webhooks.JSON.html#method=add
(delete client request)
https://mandrillapp.com/api/docs/webhooks.JSON.html#method=delete
(info client request)
https://mandrillapp.com/api/docs/webhooks.JSON.html#method=info
(list client request)
https://mandrillapp.com/api/docs/webhooks.JSON.html#method=list
(update client request)
https://mandrillapp.com/api/docs/webhooks.JSON.html#method=update