add a placeholder .mailmap
more diagnostics on failure

tests are still failing with dev Test::More releases! :(
http://www.cpantesters.org/cpan/report/8db6f00c-1d25-11e4-ba9a-f29ec7ccabfc
http://www.cpantesters.org/cpan/report/c772f47c-1ddd-11e4-bd17-df95c7ccabfc
no dump_config - on purpose
Dist-Zilla-Plugin-EnsurePrereqsInstalled-0.006-TRIAL

          - dump a few more diagnostics on test failure, to try to identify
            the problem with dev releases of Test::More