Generate entire Mapbox Style sheet in Python thread

Background

Currently, there is business logic occurring in both the Python mapboxgl library and the javascript templates. Since this is a Python library, we should isolate all business logic to Python, and make the Javascript/HTML components true templates only. This should greatly increase supportability of the mapboxgl library as it grows by isolating bugs to Mapbox GL Style Spec changes, which are much rarer than changes to the Mapbox GL JS Javascript library.

Approach

1. Generate a complete Mapbox GL Style Sheet in a Python dictionary in the viz.py
2. Serve the JSON-format style sheet to the HTML template via a the Jupyter Notebook local web server.
3. Each time the analysis updates, the templates do not need to be destroyed & recreated. The map style simply updates with map.setStyle(newStyleURL)

cc @perrygeo

[akacarlyann]

This is going to help so much with multi-layer maps if we can include the layer definitions!! Been playing around with serializing the property expressions on the Python side to get styled heatmaps layered under a point and linestring viz. Fun stuff : )

[murphy214]

This could be done with a websocket as well! As for the parsing and jinja issue, have you ever considered using something with a little more structure like a protocol buffer thats serialized as json if you knew what your were doing you could probably scrape the page with the style sheet spec on it to generate the protocol buffer structures based on the required fields etc. I’m not saying it’d be easy, in fact it’d probably be a pain but once you did once you could probably do it as things are updated (assuming that style-spec page stays up to date.) lol I may have to try this now!