Set locale in SaveToFile routine before calling json stuff.

It avoid wxWidgets alerts about locale when running some python scripts

common/settings/nested_settings.cpp

@@ -22,6 +22,7 @@
 
 #include <settings/json_settings_internals.h>
 #include <settings/nested_settings.h>
+#include <locale_io.h>
 
 NESTED_SETTINGS::NESTED_SETTINGS( const std::string& aName, int aVersion, JSON_SETTINGS* aParent,
                                   const std::string& aPath ) :
@@ -116,6 +117,8 @@ bool NESTED_SETTINGS::SaveToFile( const wxString& aDirectory, bool aForce )
     if( !m_parent )
         return false;
 
+    LOCALE_IO dummy;
+
     try
     {
         bool modified = Store();