VolumeName implementation.
Filesystems now expect volumes to have a VolumeName as their name.
Volume and VolumeService now use VolumeName for names.
Start switching IPC over to VolumeNames.
All flocker.volume tests pass.
Allow periods in identifiers.
Convert deployment logic to know just enough about namespaces.
Lint fixes.
Update documentation to note existence of namespaces.
My local spellchecker doesn't like "namespace".
Merge remote-tracking branch 'refs/remotes/origin/master' into volume-namespaces-771

Conflicts:
	flocker/volume/service.py
	flocker/volume/test/test_service.py
Fix data container integration.
Merge remote-tracking branch 'refs/remotes/origin/master' into volume-namespaces-771

Conflicts:
	flocker/node/functional/test_deploy.py
Lint fix.
Remove some mentions of Gear.
Rename GearEnvironment, remove vestigial links references and get rid of
more gear references.
Remove more references to links.
Get rid of Unit.sub_state, making Unit.activation_state documentation
more accurate.
Docker client currently only does active/inactivate states, so don't
bother with anything else.
Get rid of remaining gear references.