Make the GUI aware of the new Subordinate info.

After a recent change in juju-core, the subordinate
info is available through the mega-watcher for
services and units. This branch enables the GUI to
fully support this where possible.

Also fixed the code so that uses of "subordinate" vs
"is_subordinate" are consistent.
Add default value to units model subordinate attribute.
Improve the comments reguarding subordinate support in juju-core.
Merge pull request #558 from frankban/subordinate-in-megawatcher

Make the GUI aware of the new Subordinate info.

After a recent change in juju-core, the subordinate
info is available through the mega-watcher for
services and units. This branch enables the GUI to
fully support this where possible.

Also fixed the code so that uses of "subordinate" vs
"is_subordinate" are consistent.
Added uncommitted status attribute and the method to modify the attribute in the ecs.
Switched machine tokens to use the new commitStatus attribute to indicate the uncommitted/committed UI changes
Container tokens now use the commitStatus property to indicate which status to render
Added css class for the yellow in progress indicator for uncommitted services