Make electron webrtc working in headless and stabdard fix

Author: yciabaud

.travis.yml

@@ -4,3 +4,5 @@ node_js:
   - "node"
   - "4"
   - "0.12"
+before_script:
+  - export DISPLAY=:99.0; sh -e /etc/init.d/xvfb start

lib/client/websocket-tracker.js

@@ -90,7 +90,7 @@ WebSocketTracker.prototype.destroy = function (cb) {
   clearTimeout(self.reconnectTimer)
 
   // Destroy peers
-  for(var peerId in self.peers) {
+  for (var peerId in self.peers) {
     var peer = self.peers[peerId]
     clearTimeout(peer.trackerTimeout)
     peer.destroy()