[Classpathx-javamail] Support of multipart/*

[Robert Mitchell]

According to the Javamail specification, if a Part's content type is any
subtype of multipart, the Part's getContent() method will return a
javax.mail.Multipart (see page 17 of the 1.2 specification).
 
This does not work in Gnu's Javamail implementation:  The mailcap file
includes DataContentHandler types for many of the common subtypes of
multipart, but does not does not include one for multipart/*, which
would be the only way to implement that requirement.  In particular, I
am having problems with content of type multipart/report.
 
Thanks,
Bob Mitchell.