make really sure that [EnsurePrereqsInstalled] never runs during testing
fix creation of .latest symlink and .ackrc modification
better diagnostic info on failure
Dist-Zilla-PluginBundle-Author-ETHER-0.063

          - really fix failing tests this time (from v0.060)
          - fix updating of .ackrc file and .latest symlink in various build
            scenarios (from v0.061)