As mentioned in #18 (comment) and followup from an early PR: #10

Also, the format from diff.js gets updated by an additional function appended to diff.js for the sake of simplicity/keeping this work scoped small (that function is now named diffStyles and the previous output comes from diffStylesSetStyle), but ideally we'd remove this additional formatting function and just update the rest of the diffing function code to output to this format without further alteration.

This code feels pretty crufty since the original code was borrowed for Mapbox GL JS code to set properties and then we appended it for our purposes. This mostly works, but makes further development difficult since the code is not at all clean.

Ideally we can clean this code up to be more understandable and (probably as follow up) test it.