Establish an optional transformations stanza

[waldoj]

This ticket is an answer to #34 ("At what point do we make changes?")

We make changes within Crump, but we do so in a manner that is optional. That means creating a stanza where all of our transformations are performed, and making that optional, under a command-line switch. I think this addresses the concern raised in #29, too.

The transformations should be represented within the YAML table maps (#44) whenever possible, to keep the logic out of the Python.