ticket:10253 Fractional Plural Rules for C++, work in progress.

git-svn-id: http://source.icu-project.org/repos/icu/icu/branches/andy@33952 251d0590-4201-4cf1-90de-194747b24ca1
ticket:10253 Plural Rules, rule syntax & select() are working.

git-svn-id: http://source.icu-project.org/repos/icu/icu/branches/andy@33956 251d0590-4201-4cf1-90de-194747b24ca1
ticket:10253 Plural Rules, add '%' for 'mod'

git-svn-id: http://source.icu-project.org/repos/icu/icu/branches/andy@33957 251d0590-4201-4cf1-90de-194747b24ca1