Correct handling of aliases from CLDR

[JCEmmons]

See http://unicode.org/cldr/trac/ticket/8040 and http://unicode.org/cldr/trac/ticket/5949. We have just added locale aliases such as zh-TW -> zh-Hant-TW to cldr as languageAlias entries. Previously, I had put entries like this in their own json file called localeAliases.json, but Mark pointed out that they should rightfully go in languageAliases. So in order to keep compatibility with the "official" CLDR data, there are a few minor code changes that need to be made here.