replicator: Add refcounting to user

global: unsigned int:1 -> bool:1 perl -i -pe 's/unsigned int ([^,:;]+):1;/bool $1:1;/' **/*.[ch]

replicator: Remember last successful sync and show it in "doveadm replicator status" Patch by Matthew Via / Rackspace

doveadm replicator add <user mask> command added. This allows quickly adding users from userdb that don't exist in replicator. For example "doveadm replicator add '*'" adds all the new users from userdb. This isn't really necessary though. Users will be automatically added as soon as their mailboxes change in some way and replicator gets notified about them.

doveadm replicator replicate: Added -f parameter to force a full sync for user.

replicator: doveadm commands and user list export may have skipped some users. The users were exported from the queue, but they are temporarily removed from there while the user is being replicated. The users always exist in the hash table though.

Added "doveadm replicator remove" command to remove users from replicator queue.

doveadm replicator status: Without <usermask> parameter show overview status.

replicator: If sync fails, retry it in 5 minutes.

replicator: Added doveadm socket for communicating with "doveadm replicator".

replicator: Use stateful dsyncing whenever possible.

Initial implementation of dsync-based replication.