• avoid warning on undef input to prompts
  
• when prompting for PAUSE password, suggest that leaving it blank is
  okay
  
• tweak autogenerated files to be less likely to be misidentified as
  Prolog by Vim (ugh!) (thanks, Graham Knop!)
  
• when listing dependencies but skipping anything satisfied by core
  perl version X, do not list perl itself (if version X is good enough)
  (thanks, Leon Timmermans)