temptree: temporary trees of files

lib.rs:

Temptree creates temporary trees of files:

use temptree::temptree;

let tree = temptree! {
  foo: "a",
  bar: {
    baz: "b",
  },
};

let foo_contents = std::fs::read_to_string(tree.path().join("foo")).unwrap();
assert_eq!(foo_contents, "a");

let baz_contents = std::fs::read_to_string(tree.path().join("bar/baz")).unwrap();
assert_eq!(baz_contents, "b");