Code cleanup: remove useless wx/wx.h include inside a few files.

in most of files, including wx.h is not necessary, when only 2 or 3 wx files must be included.
Moreover, on windows, including wx.h sometimes create compil warnings about
shadowed vars defined in some specific windows headers.

common/searchhelpfilefullpath.cpp

@@ -27,6 +27,7 @@
 #include <common.h>
 #include <config.h>     // to define DEFAULT_INSTALL_PATH
 #include <macros.h>
+#include <wx/log.h>
 #include <trace_helpers.h>