Dumper.xs: Don't translate character twice

utf8_to_uvchr() already returns the native code point; no need to
convert again.  This code is only executed on Perls before 5.15
Data-Dumper/Dumper.pm: Fix for EBCDIC
perlop.pod: Fix typo that yields wrong info
XXX More regcharclass debugging
t/op/length.t: EBCDIC fixes
XXX experiment for index() failures
lib/utf8.pm: Fix pod verbatim line wrap
XXX rebase, document
XXX more regcharclass, clean up
t/op/evalbytes.t: EBCDIC fixes
t/op/utf8magic.t: EBCDIC fixes
t/uni/method.t: EBCDIC fixes
t/uni/overload.t: EBCDIC fixes