Composer support

[jackvargo]

All Submissions:

• [x ] Have you followed the Contributing guideline?
• [ x] Does your code follow the WordPress' coding standards?
• [ x] Have you checked to ensure there aren't other open Pull Requests for the same update/change?

Changes proposed in this Pull Request:

Closes Issue: 181.

How to test the changes in this Pull Request:

1. composer validate

Other information:

• [x ] Have you added an explanation of what your changes do and why you'd like us to include them?
• [ x] Have you successfully run tests with your changes locally?

Changelog entry

Added basic generic support for Composer dependency manager.

[MaryOJob]

Adding link to issue 181: #181

[andrewlimaza]

Thanks for this @jackvargo it looks good to me. We are just deciding if we want to add this to our production process.

This repository can be forked and maintained between our branch and yours where you can already use the composer support. I thought to mention this in the event of anyone that finds this Pull Request.