Debulk LED structs

[DavJCosby]

Right now, Leds are represented as follows:

pub struct Led {
    pub color: Rgb,
    position: Vec2,
    direction: Vec2,
    angle: f32,
    distance: f32,
    index: usize,
    segment: usize,
}

Meaning each takes up 56 bytes. At this scale, to represent a setup of 500 leds, 28 kilobytes of memory are required. Combine that with heavy memory footprint of the Sled struct and we run the risk of requiring more memory than some microcontrollers will be able to provide.

Decreasing the size of each LED struct make require more computational work in other places, but will make LEDs more cache friendly and therefore faster to iterate over.

There are a handful of trade-off options but here's what I'm considering:

pub struct Led {
    pub color: Rgb,
    position: Vec2,
    angle: f32,
    distance: f32,
    index: u16,
    segment: u8,
}

• 32 bytes (43% smaller, 500 leds is ~16kb)
• index and segment scaled down to smaller types
• chose angle & distance over a combined offset vector as it lets us precompute two important values at the same size. Also faster to convert from angle to direction than vice versa.

The smaller size for index and segment should have benefits all around. Filters should be smaller (and therefore Drivers), Sled gets a bit less bulky, etc etc.