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

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@39034 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

src/gtk/textctrl.cpp

@@ -16,11 +16,11 @@
     #include "wx/intl.h"
     #include "wx/log.h"
     #include "wx/utils.h"
+    #include "wx/panel.h"
 #endif
 
 #include "wx/math.h"
 #include "wx/settings.h"
-#include "wx/panel.h"
 #include "wx/strconv.h"
 #include "wx/fontutil.h"        // for wxNativeFontInfo (GetNativeFontInfo())