• IMPORTANT CHANGE: new () returns undef if it gets unsupported
  attributes. Until now, new ({ esc_char => "\" }) was just
  silently ignored. Rejecting it and failing is better than
  continuing with false assumptions.
  
• Added allow_loose_quotes (see doc)
  
• Added t/65_allow.t
  
• Added allow_loose_escapes (see doc) (RT#15076)
  
• More code cleanup in XS
  
• Added allow_whitespace (see doc)