Fixed drag and drop of unplaced units.
Implemented non-drag-and-drop unit placing workflow.
Merge branch 'fix-drop-unit' into fix-drop-unit-landing
Merge pull request #350 from makyo/driveby-flash

Quick driveby to remove the flash of charmbrowser introduced by the previous branch, just a matter of ordering.
Merge pull request #351 from huwshimi/fix-drop-unit-landing

Drag and drop of unplaced units was broken. This fixes it.

Bug: https://bugs.launchpad.net/juju-gui/+bug/1323199

QA:

drag a service to the canvas
open the machine view
drag the unplaced unit to 'create a machine'
open the javascript console and check there are no errors.
click deploy and confirm The unit should be on a new machine. Adding more units and dropping them on existing containers should work as well.
Merge pull request #341 from huwshimi/unit-placement-workflow

This is the click-through unit placement workflow.

Question: can we use constraints for creating machines/containers? If so I need to add that, if not I can remove that for now.

QA:
Use il and mv flags.
- Drag a service to the canvas. Click Deploy and Confim.
- Drag a different service to the canvas. Do not deploy.
- Open the machine view.
- In the "Unplaced units" column there should be one unit. Click the icon on the right hand side.
- A select box should appear and you should now be able to follow through with adding to a machine/container, creating new machines/containers etc. All the paths should work.