Fix #112. Enhance CANCEL request processing

Author: jmillan

Diff for: package.json

@@ -2,7 +2,7 @@
   "name": "jssip",
   "title": "JsSIP",
   "description": "the Javascript SIP library",
-  "version": "0.3.5",
+  "version": "0.3.6",
   "homepage": "http://jssip.net",
   "author": "José Luis Millán <jmillan@aliax.net>",
   "contributors": [

Diff for: src/RTCSession.js

@@ -671,15 +671,13 @@ RTCSession.prototype.receiveRequest = function(request) {
     * established.
     */
 
-    // Reply 487
-    this.request.reply(487);
-
     /*
     * Terminate the whole session in case the user didn't accept nor reject the
     *request opening the session.
     */
     if(this.status === C.STATUS_WAITING_FOR_ANSWER) {
       this.status = C.STATUS_CANCELED;
+      this.request.reply(487);
       this.failed('remote', request, JsSIP.C.causes.CANCELED);
     }
   } else {

Diff for: src/Transactions.js

@@ -635,6 +635,7 @@ Transactions.checkTransaction = function(ua, request) {
     case JsSIP.C.CANCEL:
       tr = ua.transactions.ist[request.via_branch];
       if(tr) {
+        request.reply_sl(200);
         if(tr.state === C.STATUS_PROCEEDING) {
           return false;
         } else {

Diff for: src/UA.js

@@ -460,7 +460,6 @@ UA.prototype.receiveRequest = function(request) {
         request.reply(481);
         break;
       case JsSIP.C.CANCEL:
-        request.reply(200);
         session = this.findSession(request);
         if(session) {
           session.receiveRequest(request);