Expose type definitions of the npm package

[0b5vr]

Description

I have tried to use spectorjs from Safari in my TypeScript project,
so I installed the spectorjs package from npm.
However, the type definition of the package is not exposed.
I think there is no risk to expose the type definition.

Workaround

Having spectorjs.d.ts with the content below will make the example work:

declare module 'spectorjs' {
  class Spector {
    constructor();
    public displayUI(): void;
  }
}

[sebavan]

related to #218

I guess we could manually add a typing file for the time being to support both UMD definitions ?