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

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@39285 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

src/msw/timer.cpp

@@ -18,6 +18,8 @@
 
 #if wxUSE_TIMER
 
+#include "wx/timer.h"
+
 #ifndef WX_PRECOMP
     #include "wx/list.h"
     #include "wx/window.h"
@@ -29,8 +31,6 @@
 
 #include "wx/hashmap.h"
 
-#include "wx/timer.h"
-
 #include "wx/msw/private.h"
 
 // ----------------------------------------------------------------------------