Investigation: examine cause of slowdown when zoomed very far in

[Bonkles]

Strangely, the map rendering slows way, way down when we zoom in to the map. Taking a trace shows that this is because of the pixi rendering pipeline- very little time is spent in our code.

Areas of investigation:

• turning off the dashed line generator.
• Changing the dashed line generator to useTexture mode (where it uses textures instead of geometry to draw lines, but no line caps can be used in that mode).