* enc/trans/ebcdic.trans: transcodings between EBCDIC-US
and iso-8859-1 [with code from Andrea Ribuoli]
* test/ruby/test_transcode.rb: tests for above
* tool/transcode_tablegen.rb: additional argument for
method transcode_tblgen
git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@53112 b2dd03c8-39d4-4d8f-98ff-823fe69b080e