[Spambayes] It gets funnier all the time....

[Skip Montanaro]

    If we're going to bother trying to decode base64 when no
    Content-Transfer-Encoding header is present, we might as well decode it
    when we do have one.

Whoops...  my bad.  It *is* decoded now if it's text (using .get_payload()).
It also tries to decode broken base64 text.  Now all we need is to sniff out
the real encoding if one wasn't given.

Skip