DefinitelyTyped <3

This release sees a full rewrite with TypeScript, meaning better typings for users, and a simplification in maintenance for me.

The help() command has been removed in favor of a built-in --help flag which is more common across alternative solutions, such as commander.js, and more intuitive from feedback of some users.

asStream() has been removed in favor of removing dependencies on most.js and keeping JS native solutions.

asPromise() has been renamed to withPromise to mirror the name withCallback.