Instance API design

For now we can only get `new Sinomap` instances, without public methods updating them. Imaging some of them:

* `sinomap.update()` updates map config, e.g., background color or size.
* `sinomap.destroy()` removes the map.

To dynamically update data, for now we use layers. Still looking for approaches combining layers API with sinomap instance method. Any ideas?

No file, test, or implementation entry point is named. Start by locating the public Sinomap instance API and the existing layers API, then determine how update, destroy, and dynamic data changes should interact. Done means the instance API design is agreed and its behavior is specified clearly enough to implement.

Written by the indexing model from the issue text.