Small simplification to test/functional/test_toolbox.py.
PEP-8 fixes related to tool test parsing.
Refactor tool test parsing logic out of Tool and into ToolTestBuilder.
Make formerly public methods in ToolTestBuilder private now that it does its own construction.
Refactor test data input setup logic out of TestToolBox into ToolTestBuilder.

Simplifying test_toolbox.py will hopefully make it easier to provide an alternative API driven option.
Refactor data staging and tool running logic out of test/functional/test_toolbox.py.

In a new twill specific interactor class, idea here is to proceed by implementing a matching API interactor class.
Upload a tool test's inputs in parallel.

Probably small optimization in most cases since tests generally have few inputs.