Path::Tiny always uses / -- need to use catdir instead!

as in
http://www.cpantesters.org/cpan/report/acb4805e-6c02-1014-ad85-b3b9ed261528
http://www.cpantesters.org/cpan/report/bcdc4f7f-6bfd-1014-a14e-95c6cbd1e609
use *_raw for both reading and writing, to ensure the content matches

append on MSWin32 uses :crlf, but slurp_raw does not!
e.g.
http://www.cpantesters.org/cpan/report/acb4805e-6c02-1014-ad85-b3b9ed261528
http://www.cpantesters.org/cpan/report/bcdc4f7f-6bfd-1014-a14e-95c6cbd1e609
fix tag regex to handle -TRIAL
Dist-Zilla-Plugin-Run-0.025-TRIAL

  - fix use of path separator in test to avoid more failures on MSWin32
  - fix use of :crlf mode in test to avoid yet more failures on MSWin32