better display phishing links where the phishing node contains embedded styling information
Rethinking this... by now, 2231 support is well established

Don't send broken emails to the handful of old clients that don't
support.
Better header existence checking

This really has more to do with the fact that we've been lax in IMP
checking for headers.  Even "required" headers might not exist.  These
errors will be more noticeable now that Horde_Mime_Headers is stricter
about doing existence checking, but that's a good thing.
Remove debug line
Better way of handling bad input to IMP_Message_Date
Better error handling if header doesn't exist
Add Horde_Core_Mime_Headers_Received class

createHordeHop() is Horde application specific, so it better lives in
Horde_Core rather than the more general Horde_Mime.