many changes (while on the airplane).

many changes (while on the airplane).
- reworked source error handling so that it finally works well.
- reworked ssh and imap to conform to that.
- cleaned up logging and comments all over.
- made sup-import use highline and allow the user to use previously-defined
  account information.
- made the buffer line expandable

git-svn-id: svn://rubyforge.org/var/svn/sup/trunk@135 5c8cc53c-5e98-4d25-b20a-d8db53a31250