Implement non-ASCII case conversion for Windows-1251, by Shunsuke Sato.
git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@55750 b2dd03c8-39d4-4d8f-98ff-823fe69b080e
ISO-8859-7 to be able to implement different case conversions.
git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@55652 b2dd03c8-39d4-4d8f-98ff-823fe69b080e