Create functional tests for all Debugging scenarios

[rogancarr]

As laid out in #2498 , we need scenarios to cover the Debugging functionality we want fully supported in V1.

Scenarios

• I can see how my data was read in to verify that I specified the schema correctly
• I can see the output at the end of my pipeline to see which columns are available (score, probability, predicted label)
• I can look at intermediate steps of the pipeline to debug my model.   Example: > I were to have the text "Help I'm a bug!" I should be able to see the steps where it is normalized to "help i'm a bug" then tokenized into ["help", "i'm", "a", "bug"] then mapped into term numbers [203, 25, 3, 511] then projected into the sparse float vector {3:1, 25:1, 203:1, 511:1}, etc. etc.
• (P1) I can access the information needed for understanding the progress of my training (e.g. number of trees trained so far out of how many)