Maintain YAML structure during training

[jules2689]

Problem

• Psych YAML parsing will replace comments and variable names, changing something like &class_author into &1
• :(

  Fix

• In the Preset Selector, pass back the pattern and the standardized variable name if there is one.
• Hand craft valid YAML for a domain (this assumes domains remain at the end of course, which I think is valid)
• Standardize on the pattern that seemed to be there presetType_dataType
• Write a test that validates the variable names match this standard

cc @richardwu

[richardwu]

Re-ping for another review.

[jules2689]

ping @richardwu

[richardwu]

:+1: