FreeNAS Code

Properly set arg0.

Execute autorepl.py instead of calling them in parallel.

Consistently use timedelta instead of just replacing components.

This fixes #492.

Refactor automatic replication/snapshotting process:

- Decouple replication from snapshotting. This makes it possible for the
snapshotter to take snapshots while replication is in progress.
- Implement a set of locking mechanism to prevent parallel issue.
- Protect "held" snapshots from being destroyed, this includes the last
snapshot we have replicated for an incremental transfer, the in-progress
snapshots.
- Try harder to recover from failed transfers.

remove wait and issue a terminate() to eliminate zombie process issues

send email to the admin if a replication has failed

Improve replication

PEP8 compliant; remove legacy unused code; bugfixes
Special thanks to Chyssler for pointing them out

Infrastructure for automatic remote replication.

Giant rollup commit in preperation for 8.0-RC4