http://www.iana.org/assignments/language-subtag-registry
   Type: language
   Subtag: aa
     => alpha-2 country code

   Type: language
   Subtag: aaa
     => alpha-3 country code

   Type: script
   Subtag: Aaaa
     => alpha script code

   Type: region
   Subtag: AX
     => region code

   ignore
   Deprecated: DATE

Create a new module:
   Locale::ExtLanguage - extended language codes

   Type: extlang
   Subtag: ads
   Description: Adamorobe Sign Language

   Locale::Regions - region codes

   Type: region
   Subtag: UM
   Description: United States Minor Outlying Islands

=========

Create a new package:  Locale-Codes-Links
   links codes of one type to another
      NOT necessarily 1-to-1
   function:
      link(TYPE1 [CODESET1 [CODE1]] TYPE2 [CODESET2 [CODE2]])
         => ( LINK1, LINK2, ...)     all links between types

   TYPE = Language, Script, ...
   LINK = [ CODESET1,CODE1, CODESET2,CODE2 ]

   If all 6 pieces of information are given, returns 1 if the link exists.

   Locale::Codes::Links::Language-ExtLanguage
      links ExtLanguage to Language

Based on RT-61345:

   Add support for language subtags:
      http://www.iana.org/assignments/language-subtag-registry
      http://www.w3.org/International/articles/language-tags/
