Rebased main onto cpu-clean

[tombh]

In theory this should be a working rebase, but I think I'm hitting ARM issues? This is the compile error:

total-viewsheds  tombh/cpu-clean   via 🦀 v1.92.0-nightly
󰋔 RUST_BACKTRACE=1 RUST_LOG=total_viewsheds=trace cargo run --release -- compute ../viewview/output/-13.249,57.950.bt --rings-per-km 4 --scale 100 --backend cpu --process longest-lines,total-surfaces
   Compiling total-viewsheds v0.1.0 (/publicish/Workspace/total-viewsheds/crates/total-viewsheds)
error[E0425]: cannot find value `r` in this scope
  --> crates/total-viewsheds/src/cpu.rs:96:22
   |
96 |         lhs.simd_max(r)
   |                      ^ not found in this scope

warning: the feature `generic_const_exprs` is incomplete and may not be safe to use and/or cause compiler crashes
 --> crates/total-viewsheds/src/main.rs:3:12
  |
3 | #![feature(generic_const_exprs)]
  |            ^^^^^^^^^^^^^^^^^^^
  |
  = note: see issue #76560 <https://github.com/rust-lang/rust/issues/76560> for more information
  = note: `#[warn(incomplete_features)]` on by default

warning: unused import: `slice`
  --> crates/total-viewsheds/src/cpu.rs:29:28
   |
29 | use std::{array, f32, mem, slice};
   |                            ^^^^^
   |
   = note: `#[warn(unused_imports)]` (part of `#[warn(unused)]`) on by default

error[E0277]: the trait bound `Vectorized: cpu::Viewshed<8>` is not satisfied
   --> crates/total-viewsheds/src/cpu.rs:862:41
    |
862 |     let result = total_viewshed::<8, 8, Vectorized>(
    |                                         ^^^^^^^^^^ unsatisfied trait bound
    |
    = help: the trait `Viewshed<8>` is not implemented for `Vectorized`
            but trait `Viewshed<4>` is implemented for it
note: required by a bound in `total_viewshed`
   --> crates/total-viewsheds/src/cpu.rs:634:63
    |
634 | fn total_viewshed<const WIDTH: usize, const UNROLL: usize, V: Viewshed<WIDTH>>(
    |                                                               ^^^^^^^^^^^^^^^ required by this bound in `total_viewshed`

Some errors have detailed explanations: E0277, E0425.
For more information about an error, try `rustc --explain E0277`.
warning: `total-viewsheds` (bin "total-viewsheds") generated 2 warnings
error: could not compile `total-viewsheds` (bin "total-viewsheds") due to 2 previous errors; 2 warnings emitted

Note that this PR does not plug in any tests yet.

[ryan-berger]

Closing in favor of #23