Primitive control error calculation helpers.
```toml
[dependencies]
use-control-error = "0.0.1"
```
Use `use-control-error` when you need absolute, signed, percent, or deadbanded
error helpers for explicit control calculations.
This crate is part of the `use-control` workspace. Depend on `use-control` when
you want the full facade.
This crate is experimental and may evolve while the workspace remains below
`0.3.0`.