Add py-sqlite3 back, it's needed by update mechanism.
Fix bugs and add system.device.mediachange event.
Implement disk management plugin using a bit of code from FreeNAS 9.
Add utilities:

* CacheStore for managing cached lists of objects
* filter_query for filtering Python lists in similar way to mongodb collections
Fix some bugs
Increase default dispatcher logging level for now.
Implement volume creation logic properly, add some stubs
Reflect new source files in pkg-plist.
Log all system commands executed.
Add dependency resolution between dispatcher plugins.
Adapt FreeNAS 9 zfs.py to our needs.
Fix typo.
Small fixes
Add missing CLI files in pkg-plist.
Skip logfiles in cleanvar also.