Document relation of code to Meteor Tracker

[deanrad]

Hi, great project..

I see that it is pretty comparable to the test suite of Meteor's tracker,
and is more or less a copy-paste with some ES6, but it's difficult to see where it diverges (if any), and which commit or version of Meteor's Tracker this package's 1.0.0 is based from.
https://github.com/meteor/meteor/blob/devel/packages/tracker/tracker_tests.js

Could you please explain

• which commit or version number of Meteor's Tracker this is based on
• what your goals are for keeping it up to date (and if you want maintainers)
• anything else about the why's of this project

I like that you've done it!