This is the last part of the API that belongs in public spec.

Methods supported:
- format
- derive

Options supported:
- style (decimal, scientific, currency and percent)
- pattern
- skeleton

TEST= Visit i18n.kaziprst.org/numberformat.html
Review URL: http://codereview.chromium.org/7129051

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@8379 ce2b1a6d-e550-0410-aec6-3dcde31c8c00