$unuse support

[uu-z]

let a = {
  _hooks: {
    foo: {
      bar: ({ _val }) => console.log(_val)
    }
  }
};

Mhr.$use(a);
Mhr.$use({
  "foo.bar": "hello world"
});
// should print"hello world"

Mhr.$unuse(a);
Mhr.$use({
  "foo.bar": "hello world"
});
// should not work

[uu-z]

done, but currently only support _hooks ~