int imap_renamemailbox
(int imap_stream, string old_mbox, string new_mbox)
This function renames on old mailbox to new mailbox (see imap_open() for the format of mbox names).
Returns true on success and false on error.
See also imap_createmailbox(), imap_deletemailbox(), and imap_open() for the format of mbox.