Trace first principles

[shaunlebron]

After 6 months of design and development, I would like to revisit a potentially false assumption made for #102. To this end and to better understand what Parinfer has become and what else it could it be, I wish to formally trace out the genesis of all rules that were added after the first principle of Parinfer's rule system (i.e. lisp's line invariant for formatting).

This will be another block of documentation to complement the other two:

• the [website] as a presentation of the background, goals, and implications
• the [design doc] as a guide for what exactly is happening and how, and a sprinkling of why

So this extra addition will cover why and how each rule was made and what some other possible paths are.