• Removed stray Data::Dump reference from test suite.
  
• Added the parse(), clear(), parts() and add_part() methods to
  HTTP::Message. The HTTP::MessageParts module of 5.77 is no more.
  
• Added clear() and remove_content_headers() methods to HTTP::Headers.
  
• The as_string() method of HTTP::Message now appends a newline if called
  without arguments and the non-empty content does not end with a newline.
  This ensures better compatibility with 5.76 and older versions
  of libwww-perl.
  
• Use case insensitive lookup of hostname in $ua->credentials. Patch by
  Andrew Pimlott andrew@pimlott.net.