Added ISO 639-2/T codes to i18n in addition to the ISO 639-1 codes (to support requirements for dcterms.language).
Change i18n code for ISO 639-2 lang codes to %lang-code-iso-639-2.
Added ISO-639-2 language codes for the rest of the languages.
Merge pull request #1507 from pjackson28/master

Added ISO 639-2/T codes to i18n in addition to the ISO 639-1 codes (to support requirements for dcterms.language)