add esm entrypoint and fixed cjs default export (#94)

fixed test config

removed whitespace per lint rule

Consolidated types

Version bump

Child compiler error fix (#54)

* Upgraded all depepndencies to latest

* Updated CI script.

* Configured travis for node@10.

* Added warning/error handling for child compiler instances (#53).

* Updated version

Release/2.0.0 (#50)

Refactored project to use TypeScript; increased unit test coverage.

Updated node-notifier to fix #43; added test coverage.

Updated changelog and package version

Updated node-notifier dependency to latest version to fix #45.