Change v8Locale to match proposal - constructor is different (takes settings object, not a plain string) and I've added derive method to it.

Added comments to i18n.js methods and properties, and util functions to check settings and locale validity.

Added LanguageMatcher class until ICU gets C implementation (in progress, but late for our current deadline). I added TODO to remove LanguageMatcher code. 

TEST=Visit http://i18n.kaziprst.org/locale.html.
Review URL: http://codereview.chromium.org/6901141

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@7768 ce2b1a6d-e550-0410-aec6-3dcde31c8c00