Document quality parameters better

[jpt]

I want to make quality choices clearer, possibly including some visuals to demonstrate the different parameters. It's easier to see why you might make a choice between addressing quality concerns in the Polygonizer.ts (AGG) stage vs. PathOptimizer.ts (Visvalingam-Whyatt) stage when the edge cases are in front of you. I still think the best way is to do it visually for a given use case; maybe a tool for making that easier would be useful too

[jpt]

added a wireframe mode to the examples which should make it a bit easier to see - will use this new functionality to create some screenshots of important considerations

[jpt]

I'm going to leave this open (still need better quality docs) but it occurred to me that one of the reasons V-W felt necessary is that the AGG implementation is broken :) PR on the way...

[jpt]

better AGG implementation (and VW, even if I end up removing it) being worked on in #36