Which branch of the library to release

[lord-ne]

Currently, there are three different versions of the delay code in this repository: The version in master (from the karabut branch), the version in rerewrite (my rewrite), and the version in cyacc (the cycle-accurate version by @bombela).

Before we potentially release this crate on crates.io, we need to decide which one of these versions we are going to release, and merge that version into master.

[lord-ne]

My personal opinion is we should release the cyacc implementation, since it guarantees that the delays are known at compile time, which is an important property for ensuring correctness.

I'm a little concerned about the syntax (do we really want the only way to delay on AVR in Rust to involve syntax like delay_ms::<{delay_time}>()?), which is why I introduced the macros PR, but even if that PR isn't accepted I still think it's the best version of the code.

[bombela]

Example with a number and an expression for the cycle accurate API as is:

delay_ms::<42>();
delay_cycles::<{42 * (CPU_FREQ_HZ as u64) / 1000}>();

The same example wrapped by the macros proposed by @lord-ne:

delay_ms!(42);
delay_cycles!(42 * (CPU_FREQ_HZ as u64) / 1000);