Resolve issues with no std

[kirk-baird]

Should resolve #278 and resolve #273 and also satisfy the clippy lints via cfg flags.

[GZTimeWalker]

LGTM;

[Kerollmops]

Thank you very much for the changes 🍦

However, to be sure that we don't break the code once again would it be possible to duplicate this part of the CI and change the parameters to run the tests (or at least compile) in no-std, please?

[GZTimeWalker]

Just add this part:

- name: Test
  uses: actions-rs/cargo@v1
  with:
    command: test
    args: --no-default-features

or

- name: Test
  uses: actions-rs/cargo@v1
  with:
    command: build
    args: --no-default-features

[Kerollmops]

I would say let's try with the test one, but if it doesn't pass, we can only try to build it.

[kirk-baird]

Thanks, I'll try this now and see how it goes.

[GZTimeWalker]

It seems that all the checks passed as expected.

[Kerollmops]

Thank you very much, folks 👌 I am merging this. I will do a release once #280 is merged too!