Since Thomas Wouters kept complaining that he wants access to the the

Since Thomas Wouters kept complaining that he wants access to the the
Unix From lines, change the UnixMailbox class so that _search_start()
positions the file *before* the Unix From line instead of after it;
change _search_end() to skip one line before looking for the next From
line.  The rfc822.Message class automatically recognizes these Unix
From lines and squirrels them away in the 'unixfrom' instance variable.