Improve 3x3 scramble preview aesthetics

[euphwes]

Right now all the cubies are rounded the same amount, but this isn't how real life cubes look. Start with 3x3, and see if I can adjust the polygon corner rounding to match what a real cube looks like. If it turns out to be extensible, maybe apply that to 2x2, 4x4+, and/or other events.

[euphwes]

Came up with that on the left, and asked around. Some people like the current aesthetic (right), some people like the left. Maybe I make it an option?

[topppits]

Making it an option sounds perfect. I don't mind it on 3x3, but on 5x5 for example I imagine the left view to be much easier to compare to.

[euphwes]

3 years later, finally got around to implementing this for 2x2, 3x3, and 4x4!