Replace hat module to another implementation.

[nozzy123nozzy]

Hi, The mapbox-gl-draw depends on hat 0.0.3. The hat module is licensed MIT/X11 shown in www.npmjs.com/package/hat.

MIT/X11 license must comply with the following statement,

The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.

However, at this moment,

1. The upstream of hat (github.com/substack/node-hat) is gone.
2. The installed module of the hat by npm doesn't include any copyright notice or permission notice.

Then currently, no one can comply with the license of the hat module anymore. Therefore, the mapbox-gl-draw shouldn't depend on the hat module or replace another implementation with the appropriate license.

[mourner]

Good point. Hat is only used for random ids to assign to drawn features so this should be easy to replace.