Allow override of default Locale for all internal resources

The Resources class, and therefore all our internal resources, depend on the default platform Locale.  Sometimes (and it is so in our application) we want to use a non-default Locale to display an internationalized version of the application. To accomplish this we would need to specify an override of the default platform locale that can be set and used everywhere.

I propose to add a field to Platform for this purpose, and replace calls to "Locale.getDefault()" with "Platform.getDefaultLocale()".