replace          => $boolean
         )

The locale id and English name are required, and the following formats
should used wherever possible:

 id:   languageId[_script][_territoryId[_variantId]]

 Where:  languageId = Lower case ISO 639 code -
         Always choose 639-1 over 639-2 where possible.

 script = Title Case ISO 15924 script code

 territoryId = Upper case ISO 3166 code -
               Always choose 3166-1 over 3166-2 where possible.

 variantId = Upper case variant id -
             Basically anything you want, since this is typically the
             component that uniquely identifies a custom locale.

You cannot not use '@' or '=' in locale ids - these are reserved for
future use.  The underscore (_) is the component separator, and should
not be used for any other purpose.

If the "native_*" components are supplied, they must be utf8 encoded
and follow:

If omitted, the native name is assumed to be identical to the English
name.

If class is supplied, it must be the full module name of your custom
locale. If omitted, the locale module is assumed to be a
DateTime::Locale subclass.

Examples:

 DateTime::Locale->register
     ( id => 'en_GB_RIDAS',
       en_language  => 'English',
       en_territory => 'United Kingdom',
       en_variant   => 'Ridas Custom Locale',
     );

 # Returns instance of class DateTime::Locale::en_GB_RIDAS
 my $l = DateTime::Locale->load('en_GB_RIDAS');

 DateTime::Locale->register
     ( id => 'hu_HU',
       en_language  => 'Hungarian',
       en_territory => Hungary',
       native_language  => 'Magyar',
       native_territory => 'Magyarország',
     );

 # Returns instance of class DateTime::Locale::hu_HU
 my $l = DateTime::Locale->load('hu_HU');

 DateTime::Locale->register
     ( id    => 'en_GB_RIDAS',
       name  => 'English United Kingdom Ridas custom locale',
       class => 'Ridas::Locales::CustomGB',
     );

 # Returns instance of class Ridas::Locales::CustomGB
 # NOT Ridas::Locales::Custom::en_GB_RIDAS !
 my $l = DateTime::Locale->load('en_GB_RIDAS');

If you register a locale for an id that already exists, the "replace"
parameter must be true or an exception will be thrown.

The complete name for a registered locale is generated by joining
together the language, territory, and variant components with a single
space.

This means that in the first example, the complete English and native
names for the locale would be "English United Kingdom Ridas Custom
Locale", and in the second example the complete English name is
"Hungarian Hungary", while the complete native name is "Magyar
Magyarország".  The locale will be loadable by these complete names
(English and native), via the C<load()> method.

=back

=head1 ADDING CUSTOM LOCALES

These are added in one of two ways:

=over 4

=item 1.

Subclass an existing locale implementing only the changes you require.

=item 2.

Create a completely new locale.

=back

In either case the locale MUST be registered before use.