schema: Modify AIM dependency declarations to use "app" and "imageID"

Modify the Image Manifest Schema so that it is more clear that
the dependency is refencing an app by name and an image ID.
(synchronize naming between AIM and CRM)
schema: Use "app" and "imageID" in Dependencies type.

Update example image.json to use "app" and "imageID".
Update schema Dependencies type to use the same..
schema: Fixup Name rename to App in assertValid error body.
Merge pull request #50 from cdaylward/master

schema: Modify AIM dependency declarations to use "app" and "imageID"