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

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@38920 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

src/xml/xml.cpp

@@ -21,12 +21,12 @@
 
 #ifndef WX_PRECOMP
     #include "wx/intl.h"
+    #include "wx/log.h"
 #endif
 
 #include "wx/wfstream.h"
 #include "wx/datstrm.h"
 #include "wx/zstream.h"
-#include "wx/log.h"
 #include "wx/strconv.h"
 
 #include "expat.h" // from Expat