Unified Interface to Mail Representations

Email::Abstract provides module writers with the ability to write representation-independent mail handling code. For instance, in the cases of Mail::Thread or Mail::ListDetector, a key part of the code involves reading the headers from a mail object. Where previously one would either have to specify the mail class required, or to build a new object from scratch, Email::Abstract can be used to perform certain simple operations on an object regardless of its underlying representation.
	  Email::Abstract currently supports Mail::Internet, MIME::Entity, Mail::Message, Email::Simple and Email::MIME. Other representations are encouraged to create their own Email::Abstract::* class by copying Email::Abstract::EmailSimple. All modules installed under the Email::Abstract hierarchy will be automatically picked up and used.