Sketch of flocker-deploy side of the implementation.
flocker-changestate side of the change.
Sketch of fix that restarts stopped/failed units.
More or less back to prior state, to be rebuilt TDD.
Start using NodeState as result of discover_node_configuration().
Discvoer not running units accurately.
Calculate which applications to start, restart and stop given the new information.
The interface says `IGearClient.list` should return a set, not a list.
Restart applications as necessary.
Make lint happy.
Merge remote-tracking branch 'refs/remotes/origin/master' into deploy-gather-state-279
Implement and test flocker-deploy side of the work.
Merge remote-tracking branch 'refs/remotes/origin/master' into deploy-gather-state-279

Conflicts:
	flocker/node/_config.py
Disable most of the sketch.
Lenient mode for parsing application configuration, and switch unknown
mountpoint to be None.
Another link to 289.
Tests and implementation fixes for current_from_configuration.
Hook up current state to the deployer.
Add cluster configuration parameter to flocker-changestate.
Lint fixes.