• Reordered examples in doc to show best method first
  
• Documentation grammatical fix (John P. Linderman, RT#46411)
  
• Fail if first arg to new () is not a hash ref
  
• Implement empty_is_undef on request of Evan Carroll
  
• Typo in documentation (Herwin Weststrate, RT#47613)
  
• error_diag () uses warn () in void context instead of STDERR
  
• Add auto_diag attribute (still under construction)
  
• FIX: reset attributes (after they have been set) with accessor