Add a workspace for standalone development.
Pull dependencies from the workspace.
Scheme version bump.
Document the workspace.
Merge pull request #279 from MantleFramework/flatten-dependencies

Flatten dependencies
Merge branch 'master' into 2.0-development
Merge branch '2.0-development' into longer-lived-adapters
WS
Use id as return value for models
Add -filterPropertyKeys:forModel:
Bump Deployment Target to 10.8/6.0
Cache transformers and mappings in MTLJSONAdapter