Copy updated files from lib9/utf from upstream repository.

This also requires updating code that previously took a shortcut and
depended on the Rune and char32 typedefs to be identical (which is no
longer the case, as Rune is now unsigned).

R=jia.shao.peng@gmail.com
BUG=

Review URL: https://codereview.appspot.com/136920043

git-svn-id: http://libphonenumber.googlecode.com/svn@699 ee073f10-1060-11df-b6a4-87a95322a99c