Refresh list of unplaced units on DB updates.
Merge pull request #305 from kadams54/unplaced-units-render

### QA

With `/:flags:/il/mv/`, switch to the machine view. Select a charm in the browser and then click on "Add to my canvas". When the details panel closes, you should see the unplaced service sitting in the Unplaced Units column.
UI polish

* Fixed duplicate deployer bar controls
* Added machines/containers to summary.
Lint; constraints.
Added test
Merge pull request #312 from makyo/deployment-summary

* Fixed duplicate deployer bar controls
* Added machines/containers to summary.

To QA, from the console:
```javascript
app.env.addMachines([{}]);
app.env.get('ecs').changeSet; // note the machine key
app.env.addMachines([{parentId: '<machine key>', containerType: 'lxc'}]);
```
Check the deployer bar and deployment summary for the changes.

This is an intermediate branch pending @frankban's work on placeUnit