Updated copyright notices to include the year 2018.

Updated copyright notices to include the year 2017.

imap-hibernate: Increased imap-master communication timeout from 5s to 30s Looks like 5s isn't enough in loaded environments. It's also not really a problem if the timeout is large, it's just going to take a while longer to restore the connection. When timeout is reached the client would just get disconnected anyway.

imap-hibernate: If un-hibernation failed due to timeout, log whether we saw version line. Could help with debugging.

imap-hibernate: If imap-master socket is busy, retry un-hibernation later.

global: freshen copyright git ls-files | xargs perl -p -i -e 's/(\d+)-201[0-5]/$1-2016/g;s/ (201[0-5]) Dovecot/ $1-2016 Dovecot/'

Added imap-hibernate process for gathering IDLEing imap processes. imap_hibernate_timeout setting controls how quickly the connection is moved from imap process to imap-hibernate process. Some IMAP extensions like NOTIFY, SEARCH=CONTEXT and COMPRESS aren't supported yet. There's also a new X-STATE command, which can be used to export the current IMAP connection state to a string and later on imported to get back to the original state (a quick resync feature for IMAP clients). However, this command is disabled for now due to the current code being unoptimized for untrusted input.