Log Message:
- updated to 2.004
- took maintainership

Changelog:
2.004     2008-06-25
          publicize default_header_class method
          remove the long-deprecated Headers.pm

2.003     2007-07-19
          improve tests, for 5.5 compat
          remove conditional circular prereq on Email::MIME, replace it with a
          warning and delay

2.002     2007-07-14
          change initialization order to unbreak Email::MIME
          do not return ->body from ->body_set to simplify subclass behavior

2.001     2007-07-13
          fix t/perl-minver.t to properly skip if T::MV not installed
          retroactively set 2.000 release date!

2.000     2007-07-13
          huge improvement to speed of bodyless message parsing
            pointed out by Dan Dascalescu; thanks!
          more documentation of header class
          new Header crlf defaults to real CRLF
          fix tests to avoid requiring 5.6