Include wx/event.h according to precompiled headers of wx/wx.h (with other minor cleaning).

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@38939 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

src/unix/joystick.cpp

@@ -16,6 +16,10 @@
 
 #include "wx/joystick.h"
 
+#ifndef WX_PRECOMP
+    #include "wx/event.h"
+#endif //WX_PRECOMP
+
 #include <linux/joystick.h>
 #include <sys/types.h>
 #include <sys/stat.h>
@@ -24,7 +28,6 @@
 #include <fcntl.h>
 #include <unistd.h>
 
-#include "wx/event.h"
 #include "wx/window.h"
 #include "wx/unix/private.h"