IMAP: cleanup datefield header-caching
lower loglevel for deprecation warning
IMAP: fix order of headers in fetch
POP3: fix crash after too many errors
IMAP: fix sort while searching headers
3_1 backport: load-test the write-event handling
3_1 backport: fix hanging deamon
3_1 backport: give up trying to write to clients after fatal errors
IMAP: load-testing
POP: plug file-descriptor leak

regression introduced in b9da933bebb082c36cf060d43ddd146fd74b4e2a
ssl cleanups
bump and tag 3.1.3