Simple fetch and unroll .tar.gz archives

Simple functions intended to use in Rust build.rs scripts for tasks which related to fetching from HTTP and unrolling .tar.gz archives with precompiled binaries and etc.

Usage example

use fetch_unroll::Fetch;

let pack_url = format!(
    concat!("{base}/{user}/{repo}/releases/download/",
            "{package}-{version}/{package}_{target}_{profile}.tar.gz"),
    base = "https://github.com",
    user = "katyo",
    repo = "aubio-rs",
    package = "libaubio",
    version = "0.5.0-alpha",
    target = "armv7-linux-androideabi",
    profile = "debug",
);

let dest_dir = "target/test_download";

// Fetching and unrolling archive
Fetch::from(pack_url)
    .unroll().strip_components(1).to(dest_dir)
    .unwrap();