transcode.c (rb_cEncodingConverter): new class Encoding::Converter.
(econv_free): new function.
(econv_s_allocate): ditto.
(econv_init): ditto.
(check_econv): ditto.
(econv_primitive_convert): new method.
(Init_transcode): define Encoding::Converter.
(econv_free): new function.
(econv_s_allocate): ditto.
(econv_init): ditto.
(check_econv): ditto.
(econv_primitive_convert): new method.
(Init_transcode): define Encoding::Converter.
git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@18544 b2dd03c8-39d4-4d8f-98ff-823fe69b080e