Log Message:
Update to 0.28

Upstream changes:
0.28 Thu Mar 14 2013
        [FIXES]
        - the Accept-Encoding header removal code was broken in the previous
          version. Now the header will be removed as soon as a body filter
          is configured.
        [TEST]
        - use File::Spec in the test suite to compute portable file names,
          to avoid some test failures, like
          http://www.cpantesters.org/cpan/report/856ca676-6bf5-1014-bfa1-9d8aa3912248

0.27 Fri Mar  8 2013
        [IMPROVEMENTS]
        - in HTTP::Proxy::HeaderFilter::standard, now remove the Accept-Encoding \ 
header
          only when we know we'll actually look at the response body
        [TESTS]
        - use httpstat.us to test HTTP statuses

0.26 Wed Feb  6 2013
        [IMPROVEMENTS]
        - remove a "Use of "goto" to jump into a construct is \ 
deprecated"
          warning (Tom Hukins)
        [DOCUMENTATION]
        - fix RT #77685 (Tom Hukins)
        - improved the number of links to other modules from the documentation
        [TEST]
        - fix RT #71771 (Tom Hukins)
        - fix test failures in POD tests (Tom Hukins)