* Add basic CONDSTORE support when fetching initial messages.
* Add utility functions for QRESYNC support.
* Add QRESYNC support.
* Add more doc for the $imap_condstore and $imap_qresync options.
* Only sync CONDSTORE and QRESYNC on the initial download.
* Allow ctrl-c to interrupt initial IMAP header download.
* Fix nested macro warning.
* tidy upstream changes