Simple fetch and unroll .tag.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

```rust use fetchunroll::fetchunroll;

let packurl = format!( "{base}/{user}/{repo}/releases/download/{ver}/{pkg}{prof}.tar.gz", base = "https://github.com", user = "katyo", repo = "oboe-rs", pkg = "liboboe-ext", ver = "0.1.0", prof = "release", );

let destdir = "target/testdownload";

// Creating destination directory std::fs::createdirall(dest_dir).unwrap();

// Fetching and unrolling archive fetchunroll(packurl, dest_dir).unwrap(); ```