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/generic/panelg.cpp

@@ -30,10 +30,10 @@
     #include "wx/colour.h"
     #include "wx/settings.h"
     #include "wx/log.h"
+    #include "wx/panel.h"
 #endif
 
 #include "wx/containr.h"
-#include "wx/panel.h"
 
 // ----------------------------------------------------------------------------
 // wxWin macros
@@ -179,4 +179,3 @@ void wxPanel::OnSize(wxSizeEvent& event)
 
     event.Skip();
 }
-