* POSIX::strftime doesn't know about encodings and doesn't return a utf8

* POSIX::strftime doesn't know about encodings and doesn't return a utf8
  flagged string even if the locale causes it to generate utf8 output,
  so make sure to let perl know it should be handled as utf8. Also,
  the optimised version used for standard time formats won't work if the
  user has changed locale, so drop it. Thanks, Faidon Liambotis.
* Fix re-encoding of the comments field to utf8 if a commit fails
  due to a conflict. Thanks, Faidon Liambotis.
* Let svn know that commits have utf8 commit messages. Thanks, Faidon
  Liambotis.
* Add insane double encode/decode to utf8 around call to markdown.
  This works around a truely strange bug, which is apparently a bug in
  perl, which I lack space to describe here (see t/crazy-badass-perl-bug.t)