Housekeeping edition

Most of this is housekeeping to bump dependency versions, fix testability due to dependency changes, etc.

Now requires Node 6+.

Also, updates to add better async/await support and handling of empty streams.

A New Hope Edition

Hello, my name is @Kikobeats and I'm a new maintainer of x-ray project. Nice to meet you!

I'm happy to say that this version have a lot of changes aligned to make easy contribute with the project.

General

• Added Travis and Coveralls integration to be sure that PR don't break code. 🙌
• Refactored a LOT. Extracted dirty logic for hide complexity and make clean use API.
• Moved phantom tests into x-ray-phantom
• Moved CLI into a separate project (still in progress).
• Priorized issues under labels.

API

• Added .stream method that follow the same behavior that .write wihtout parameters (more semantic)

What's next

• Better stream support.
• Better interaction with request object (like setup headers/cookies).