A3t

- Added tree accessor.
Alias

- Broke out alias handling into a separate object.
Alias

- Integrated new Alias object into new command line processing.
A3t

- Removed obsolete ::findAliases method.
A3t

- Removed diagnostics.
I18N

- Updated all L10N language/country references to use ISO 639-3 (language)
  and ISO 3166-1 alpha 3 (country) codes.
- Note that holiday files are not updated.