Add support for na / nalgebra crates?

[sunsided]

Can we make use of na types (even if we may run our own implementation)?

[sunsided]

One big issue to deal with is that nalgebra is column-major by default, whereas minikalman assumes row-major matrices. While it is possible to expose minikalman matrices to nalgebra (#29 started that), the other way around is much more involved.

[justpresident]

There are ton of kalman filter implementations and all of them use nalgebra. This is the only one that doesn't depend on nalgebra.
The problem with nalgebra is that it has a ton of dependencies which bloat the binary excessively. I wasn't able to use any other crate with atmega328p

[sunsided]

@justpresident That's a great point, thank you! I was thinking about making it an optional dependency in the first place, but to hear that it might actually be a feature not to have it in the first place didn't cross my mind.