Send adaptive program queries to Agent

[UserAB1236872]

We need to be able to query the agent for feedback on a game state during replays for explanation stuff. This will be evolving a lot, my first intuition is that we should provide some simple visualization primitives (more high level than what the backend uses) like "pie chart", "heatmap", "highlight entity" etc. We need to take care to not reinvent an entire plotting package.

Since we're using JS, something like bokeh is out, but we may be able to find some nice JS plotting libraries to lighten the load. (Which is a shame, it'd be nice to send rendered graphs from bokeh, they look quite nice).

Depends, minimally on #14, #16, #17, #18 + some API and protobuf consideration

[UserAB1236872]

This may be a good JS library to use but I'll let @jedirv decide

http://www.chartjs.org/

[jedirv]

Jed note - this is the question of how to query the agent for explanations. For first demo deliverable, just doing saliency which is more straightforward. leave this open for post demo1.