Verb/config (#32)

* add config verb

* more docs

* minor

* more docs

* add some properties to gather

* additional gather options

* more gather opts

* add support for dtmf verb

* 0.7.4 release notes

* dial referHook details

markdown/docs/webhooks/dial.md

@@ -57,6 +57,7 @@ You can use the following attributes in the `dial` command:
 | dtmfHook | a webhook to call when a dtmfCapture entry is matched.  This is a notification only -- no response is expected, and any desired actions must be carried out via the REST updateCall API. | no|
 | headers | an object containing arbitrary sip headers to apply to the outbound call attempt(s) | no |
 | listen | a nested [listen](#listen) action, which will cause audio from the call to be streamed to a remote server over a websocket connection | no |
+| referHook | webhook to invoke when an incoming SIP REFER is received on a dialed call.  If the application wishes to accept and process the REFER, the webhook application should simply return an HTTP status code 200 with no body, and jambonz will send a SIP 202 Accepted.  Otherwise, any HTTP non-success status will cause jambonz to send a SIP response to the REFER with the same status code.  <br/><br/>Note that jambonz will send the 202 Accepted and do nothing further.  It is the responsibility of the third-party application to then outdial a new call and bridge the other leg, presumably by using the REST API.  See [this example app](https://github.com/jambonz/sip-blind-transfer) for more details.| no|
 | target | array of to 10 [destinations](#target-types) to simultaneously dial. The first person (or entity) to answer the call will be connected to the caller and the rest of the called numbers will be hung up.| yes |
 | timeLimit | max length of call in seconds | no |
 | timeout | ring no answer timeout, in seconds.  <br/>Defaults to 60. | no |