imap: Changed the order of the response types in imap_endofresp()

From a maintenance point of view the code reads better to view tagged
responses, then untagged followed by continuation responses.

Additionally, this matches the order of responses in POP3.
imap: Added check for new internal imap response code
darwinssl: fix undefined $ssllib warning in runtests.pl

I also added --with-darwinssl to the list of SSL options in configure.