Sketch the additional requirements for the calculate state changes api
Merge branch 'deploy-gather-state-279' into determine-volume-changes-272

Conflicts:
	flocker/node/_deploy.py
	flocker/node/test/test_deploy.py
Cleanups: make tests more likely to run correctly, disable new code for now.
Calculate volumes to create.
Calculate volumes to wait for.
Calculate volumes that need to be handed off.
Calculate no actions for volumes that require no movement.
Lint fixes.
Merge remote-tracking branch 'refs/remotes/origin/master' into determine-volume-changes-272
Address review comment: Misspeak.
Address review comment: more accurate comments.
Address review comment: explain what the issue is.
Address review comment: More sensible image name.
Address review comment: typo.
Address review comment: Note another missing feature.
Merge pull request #372 from ClusterHQ/determine-volume-changes-272

Determine necessary volume changes as part of a deploy.

Fixes #272.