Better strokeWeight default to account for new line perspective feature

[TiborUdvari]

The new line perspective feature introduced in p5.js v1.9.2 makes it so all examples, especially in AR look buggy. Since WebXR uses real world measurements, especially in immersive-ar mode this means that lines will have a thickness of 1m. Will add a way to add better defaults.

Here you can see the same sketch with v1.9.1 vs v.1.9.2 which introduces the new linePerspective feature.

This is related to what I thought broke in #219

push();
translate(0, 0, -0.4);
box(0.1, 0.1, 0.1);
pop();