title: Changing NumberConstants.decimalSeparator() value
body: <p>I'm working with NumberField and NumberFormat.
  How can I change NumberConstants.decimalSeparator() value without changing my locale? For instance I want to have "." or "," as decimal separators for all locales.
  Is it possible to create custom property file NumberConstants_bla.properties and force gxt use it instead of standard NumberConstants_ru_RU.properties or NumberConstants_en_US.properties (depending on current locale)? Where should I place this file to?</p>