Moved changed nextPresenter to return a promise
Removed dead method
Moved presenter lookup out of workflow into app
Removed references to application in workflow engine
Moved pipeline config into workflow engine
Workflow engine becomes a function!
Add default printers to rack scan
- RackScan is inconsistent with the step presenter here
Merge pull request #214 from seandunn/workflow_engine_as_function

Workflow engine as function