FreeNAS Code

Rework r8033 so the control can happen at one single point.

Don't emit informational every minute when listing the snapshots. This is confusing and noisy.

Fixes ticket 459 and various confusing customer questions (we can always enable verbose debug mode later).

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