Make run_calculator obselete in preference of a modified Calculator.run()

[elinscott]

Currently Workflow.run_calculator(), and Workflow.run_calculator_single() is a very clumsy way of creating calculators and giving these functions access to the workflow object.

Instead, there should be a Calculator objects should be given a workflow attribute that points back to the Workflow object, and then calc.run() should be able to do everything Workflow.run_calculator() currently does

Among other things, this will require...

• calc.workflow to not be included in the json, but for calc.workflow to be recovered when loading a Workflow from json
• the StumblingWorkflow to be rewritten because it redefines run_calculator_single()

It may also be worth thinking about if Workflow.new_calculator() is the best way of creating new calculators.