Zend_Mime_Message represents a MIME compliant
message that can contain one or more separate Parts (Represented as Zend_Mime_Part objects). With
Zend_Mime_Message, MIME compliant multipart
messages can be generated from Zend_Mime_Part objects. Encoding
and Boundary handling are handled transparently by the class.
Zend_Mime_Message objects can also be reconstructed from given
strings (experimental). Used by Zend_Mail.
