Add missing include.

Com_server/include/PixhawkServer.h

+/**
+ *  @author Sylvain Colomer
+ *  @date 18/04/19.
+ */
+
+#ifndef PIXHAWK_SERVER_H
+#define PIXHAWK_SERVER_H
+
+#include <common/mavlink.h>
+
+#include <cstdlib>
+#include <iostream>
+#include <stdio.h>  
+#include <unistd.h> 
+#include <fcntl.h>  
+#include <time.h>
+#include <sys/time.h>
+
+#include "blc_channel.h"
+#include "blc_program.h"
+
+#include "Data_Drone.h"
+
+#include "Com_SerialReadingThread.h"
+#include "Com_SerialWritingThread.h"
+#include "Display_IHM.h"
+
+
+
+void command_loop();
+
+#endif