Existing update commands should expose generic update fields

[tjprescott]

For consistency across commands, and to fill any gaps that may occur when a service exposes new functionality before a CLI rev, we should expose the generic update parameters (--add --set --remove) on each of our existing update commands.

The generic update is currently assembled from a setter and a getter, with common code to handle the generic parameters. We should be able to relatively easily insert our existing custom commands into that flow.

The recommended execution order would be:

1. Call the getter to retrieve the object.
2. Pass the object into the custom command (this will require removing the getter and setter statements from the existing custom command and adding a parameter for the object)
3. Pass the object on to the standard generic update code.
4. Pass the object to the setter.

[tjprescott]

PR #735 merged.