one part. If it is a MIME message with multiple parts ("attachments") all parts
are decoded. Decoding can be controlled by command-line options.
+WHAT'S NEW in version 2.3.1 (2014-01-31)
+ Update documentation.
+
WHAT'S NEW in version 2.3.0 (2014-01-30)
Add option -o and output_file argument.