add percentiles to summary output

[JackKCWong]

I change the Stat::new to mutable borrow the input vec to avoid copying, except for the xyplot where original order matters. Let me know what you think. Cheers.

[JackKCWong]

tests passed.

[juan-leon]

Thanks for the pull request. Having percentiles is nice.

The Test pipeline failed (it seems fixable with cargo fmt).

If you have make tool installed you can do make pre-commit to make sure changes are OK. Otherwise, this will do the job:

cargo fmt -- --check
cargo test -- --test-threads 1
cargo clippy -- -D clippy::all

[JackKCWong]

cargo fmt -- --check

Should have run make pre-commit! Fixed now. Thanks.

[juan-leon]

Excellent!

Thanks for your contribution

[juan-leon]

Created release v0.5.9 with this change