dev-proxy-logging: Add client ip transference to proxy server.

- Add rewriting 'X-REAL-IP' header for each request through dev
  proxy server.
- Change webpack configuration ip to 0.0.0.0 to fix socket.io build
  for launching remote dev server.

tools/run-dev.py

@@ -288,6 +288,8 @@ class CombineHandler(BaseWebsocketHandler):
     @web.asynchronous
     def prepare(self):
         # type: () -> None
+        if 'X-REAL-IP' not in self.request.headers:
+            self.request.headers['X-REAL-IP'] = self.request.remote_ip
         if self.request.headers.get("Upgrade", "").lower() == 'websocket':
             return super(CombineHandler, self).prepare()
         url = transform_url(