ZFS snapshot replication support:

* zserver: serves snapshots registered locally via zclient.  Can send
  a full snapshot or an incremental diff over a TCP or UNIX domain
  socket. 

* zclient: command-line interface to the snapshot server.

* zsync: simple script for synchronizing a locally cached snapshot
  with the server.  Needs additional error handling

* insta-jail: proof of concept using zsync and zfs clones to
  instantiate a jail image.  Will be extended to also take care of
  staging data in/out of the jail and providing additional
  configuration (packages, source trees, etc).