Feature/incoming refer (#76)

* Dial: handle incoming REFER on either leg by calling referHook, if configured

* lint

* modify payload of referHook

* support target.trunk on rest createCall api

* bugfix: gather partial result hook was not working

* lint

* handling of incoming REFER

lib/session/adulting-call-session.js

@@ -30,15 +30,25 @@ class AdultingCallSession extends CallSession {
     return this.sd.dlg;
   }
 
+  /**
+   * Note: this is not an error.  It is only here to avoid an assert ("no setter for dlg")
+   * when there is a call in Session:_clearResources to null out dlg and ep
+   */
+  set dlg(newDlg) {}
+
   get ep() {
     return this.sd.ep;
   }
 
+  /* see note above */
+  set ep(newEp) {}
+
   get callSid() {
     return this.callInfo.callSid;
   }
 
-
+  _callerHungup() {
+  }
 }
 
 module.exports = AdultingCallSession;