Fix boost::asio misuse that would cause lag

io_service::reset was not called before io_service::poll, meaning that new events would be really polled in the next Connection::poll call, this could lead to network lag in computers with low framerate (ie: a user with 10 fps would have 100ms lag just because of that)

src/framework/net/connection.cpp

@@ -50,8 +50,9 @@ Connection::~Connection()
 
 void Connection::poll()
 {
-    g_ioService.poll();
+    // reset must always be called prior to poll
     g_ioService.reset();
+    g_ioService.poll();
 }
 
 void Connection::terminate()