Use the libm crate for a full Float on no_std

[cuviper]

Currently, num_traits::Float is only available with std, and no_std only has the more limited FloatCore without all of transcendental functions like sqrt, sin, etc. The new libm crate might be the way out of this, as an optional dependency to get Float on no_std too!

There's also Real and the signed and floating-point Pow (mapping to powi and powf) which all require std now, and should be feasible with libm. I'm not sure about MulAdd and MulAddAssign though.

[vks]

libm is not ready yet, it panics with overflows in debug mode.

[cuviper]

Sure, we can hold off until it's more ready -- I'm not in any rush. It could still be useful to do early exploration though, to identify any other shortcomings that libm might want to address.

[malobre]

Since #99 was merged shouldn't this be closed ?

Edit: If closing please also consider publishing a new version this would permit updating other crates (Ogeon/palette#145) thanks :)

[korken89]

Hi, please make a release including #99 this is a key component for a library I'm writing and I would love to have this!

CC @cuviper