Expand IStoragePool to include enumeration.  Also a test.  And an implementation for the in-memory version.
Quick and dirty implementation of the new method for the zfs version too.
testing
Not volumes at this level: filesystems.
Some unit tests for volume enumeration.
Merge remote-tracking branch 'origin/master' into list-volumes-48
Merge 'master' into rpm-9.
Remove twisted.plugins from setup.py.
Need setuptools to install.
Need pytz for tests.
We don't ship a plugin anymore.
Fix a mis-use of characteristic and fix a mis-implementation of VolumeService.enumerated.
Correct some mistaken uses of "volume" with "filesystems".
Merge remote-tracking branch 'origin/master' into list-volumes-48
Fix a couple PEP8 issues and link to an issue about how this implementation is fragile.
docstring for one of the parser helpers
Merge remote-tracking branch 'origin/master' into list-volumes-48

Conflicts:
	flocker/volume/filesystems/memory.py
	flocker/volume/test/test_service.py
get_mountpoint has changed to get_path, compensate for that
Added some docstrings
Moved comment to more relevant place