Optimized polygon rendering

[coolbutuseless]

A better optimized polygon rendering algorithm would be nice to have, but is not a priority for the initial release.

Optimizations:

• Use an active edges list
• Use Bresenham-style position updating to efficiently update the polygon edges at every new scanline.
• polygon clipping? Not sure if "juice is worth the squeeze". Does the time spent clipping save enough compared to when it comes time to actually render?

Probably best to start this as a new function in C, and just leave the old one for reference.

References:

• https://medium.com/@dillihangrae/scanline-filling-algorithm-852ad47fb0dd
• https://graphics.stanford.edu/courses/cs248-05/proj2help/assignment2help.pdf
• https://uea-teaching.github.io/graphics1-2022/lectures/polygon-filling.html#/scan-line-algorithm