Fix #176. Update to the latest IceServer definition

Old:

dictionary RTCIceServer {
    DOMString  url;
    DOMString? credential;
};

New:

dictionary RTCIceServer {
    (DOMString or sequence<DOMString>) urls;
    DOMString?                         username = null;
    DOMString?                         credential;
};

Note: Current Firefox Nightly "28.0a1 (2013-11-18)" Does not support multiple 'urls'

src/RTCSession/RTCMediaHandler.js

@@ -105,24 +105,19 @@ RTCMediaHandler.prototype = {
   * @param {Function} onSuccess Fired when there are no more ICE candidates
   */
   init: function(constraints) {
-    var idx, length, server, scheme, url,
+    var idx, length, server,
       self = this,
       servers = [],
       config = this.session.ua.configuration;
 
-    length = config.stun_servers.length;
-    for (idx = 0; idx < length; idx++) {
-      server = config.stun_servers[idx];
-      servers.push({'url': server});
-    }
+    servers.push({'url': config.stun_servers});
 
     length = config.turn_servers.length;
     for (idx = 0; idx < length; idx++) {
       server = config.turn_servers[idx];
-      url = server.server;
-      scheme = url.substr(0, url.indexOf(':'));
       servers.push({
-        'url': scheme + ':' + server.username + '@' + url.substr(scheme.length+1),
+        'url': server.urls,
+        'username': server.username,
         'credential': server.password
       });
     }

src/UA.js

@@ -1088,7 +1088,7 @@ UA.configuration_check = {
     },
 
     turn_servers: function(turn_servers) {
-      var idx, length, turn_server;
+      var idx, length, turn_server, url;
 
       if (turn_servers instanceof Array) {
         // Do nothing
@@ -1099,14 +1099,32 @@ UA.configuration_check = {
       length = turn_servers.length;
       for (idx = 0; idx < length; idx++) {
         turn_server = turn_servers[idx];
-        if (!turn_server.server || !turn_server.username || !turn_server.password) {
+
+        // Backward compatibility:
+        //Allow defining the turn_server url with the 'server' property.
+        if (turn_server.server) {
+          turn_server.urls = [turn_server.server];
+        }
+
+        if (!turn_server.urls || !turn_server.username || !turn_server.password) {
           return;
-        } else if (!(/^turns?:/.test(turn_server.server))) {
-          turn_server.server = 'turn:' + turn_server.server;
         }
+
+        if (!turn_server.urls instanceof Array) {
+          turn_server.urls = [turn_server.urls];
+        }
+
+        length = turn_server.urls.length;
+        for (idx = 0; idx < length; idx++) {
+          url = turn_server.urls[idx];
+
+          if (!(/^turns?:/.test(url))) {
+            url = 'turn:' + url;
+          }
 
-        if(JsSIP.Grammar.parse(turn_server.server, 'turn_URI') === -1) {
-          return;
+          if(JsSIP.Grammar.parse(url, 'turn_URI') === -1) {
+            return;
+          }
         }
       }
       return turn_servers;